openapi: 3.2.0
info:
  version: 1.0.0
  title: Customer.io App Newsletter Variants API
  description: 'Our App API provides ways to trigger messages and retrieve information about people, campaigns, broadcasts, and more.


    # Overview


    The App API provides methods to send newsletters, transactional messages, and API-triggered broadcasts. You can create newsletters from scratch and update transactional messages and API-triggered broadcasts.


    For transactional messages and API-triggered broadcasts, your payload acts as a message "trigger" and can contain `data` that you reference in your messages using liquid—`{{trigger.<data>}}`.


    The other endpoints help you retrieve information about people, segments, campaigns, broadcasts, etc; it also lets you update campaign actions, messages, newsletter variants, etc. Aside from the [API-triggered broadcast](#triggerBroadcast) (1 per 10 seconds) and [Transactional](#sendEmail) (100 per second) endpoints, requests are limited to 10 per second.


    # Use our Postman collection


    We''ve generated a Postman collection to help you get started with our APIs.


    If you fork this collection, you might want to disable the *Watch original collection* option. We automatically update our Postman collection whenever we release changes to our documentation, even if we don''t change our APIs—which happens daily! Rather than being flooded with Postman notifications, you can check out our [Release Notes](/release-notes/) for updates to our APIs.


    **NOTE**: Postman endpoints default to our US APIs. If you''re in our European (EU) region, you''ll need to add `-eu` to the server variables (`track_api_url` and `app_api_url`).


    [<img src="https://run.pstmn.io/button.svg" alt="Run In Postman" style="width: 128px; height: 32px;">](https://god.gw.postman.com/run-collection/23697545-2931c004-e63d-4cdc-bf4b-e685ba6da42d?action=collection%2Ffork&source=rip_markdown&collection-url=entityId%3D23697545-2931c004-e63d-4cdc-bf4b-e685ba6da42d%26entityType%3Dcollection%26workspaceId%3Db886877f-fc09-475f-84fe-6221a98f4d18#?env%5BCustomer.io%20API%20Environment%5D=W3sia2V5IjoidHJhY2tfYXBpX3VybCIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiJ0cmFjay5jdXN0b21lci5pbyIsImVuYWJsZWQiOnRydWV9LHsia2V5IjoiYXBwX2FwaV91cmwiLCJ0eXBlIjoiZGVmYXVsdCIsInZhbHVlIjoiYXBpLmN1c3RvbWVyLmlvIiwiZW5hYmxlZCI6dHJ1ZX0seyJrZXkiOiJzaXRlX2lkIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5IjoiYXBpX2tleSIsInR5cGUiOiJzZWNyZXQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5IjoiYmVhcmVyIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5IjoiYnJvYWRjYXN0X2lkIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5IjoiaW1wb3J0X2lkIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5IjoiZW1haWxfYWRkcmVzcyIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6InN1cHByZXNzaW9uX3R5cGUiLCJ0eXBlIjoiZGVmYXVsdCIsInZhbHVlIjoiIiwiZW5hYmxlZCI6dHJ1ZX0seyJrZXkiOiJjb2xsZWN0aW9uX2lkIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5Ijoic25pcHBldF9uYW1lIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5Ijoid2ViaG9va19pZCIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6InNlbmRlcl9pZCIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6ImV4cG9ydF9pZCIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6Im1lc3NhZ2VfaWQiLCJ0eXBlIjoiZGVmYXVsdCIsInZhbHVlIjoiIiwiZW5hYmxlZCI6dHJ1ZX0seyJrZXkiOiJzZWdtZW50X2lkIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5IjoibmV3c2xldHRlcl9pZCIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6ImNvbnRlbnRfaWQiLCJ0eXBlIjoiZGVmYXVsdCIsInZhbHVlIjoiIiwiZW5hYmxlZCI6dHJ1ZX0seyJrZXkiOiJjYW1wYWlnbl9pZCIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6ImFjdGlvbl9pZCIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6ImN1c3RvbWVyX2lkIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5IjoidHJhbnNhY3Rpb25hbF9pZCIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6InRyaWdnZXJfaWQiLCJ0eXBlIjoiZGVmYXVsdCIsInZhbHVlIjoiIiwiZW5hYmxlZCI6dHJ1ZX0seyJrZXkiOiJmb3JtX2lkIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9LHsia2V5IjoiaWRlbnRpZmllciIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6ImRldmljZV9pZCIsInR5cGUiOiJkZWZhdWx0IiwidmFsdWUiOiIiLCJlbmFibGVkIjp0cnVlfSx7ImtleSI6ImRlbGl2ZXJ5X2lkIiwidHlwZSI6ImRlZmF1bHQiLCJ2YWx1ZSI6IiIsImVuYWJsZWQiOnRydWV9XQ==)


    # Server addresses: US and EU


    Customer.io hosts services in the United States (US) and European Union. Select the appropriate server address for your region.


    | Region | Server Address |

    | :-- | :-- |

    | US | https://api.customer.io |

    | EU | https://api-eu.customer.io |


    # Authentication


    All requests to the Customer.io App API use an [App API Key](#App-API-Key).


    To authenticate, provide your key as a Bearer token in a HTTP Authorization header. You can create and manage your API keys—including keys with different scopes—in [your account settings page](https://fly.customer.io/settings/api_credentials?keyType=app). Each operation on this page references the authorization header it requires.


    # Rate Limits


    Most endpoints on this page are limited to 10 requests per second. The exceptions are:

    * The [transactional email](#operation/sendEmail) endpoint is limited to 100 requests per second.

    * The [API-triggered broadcast endpoint](#operation/triggerBroadcast) is limited to 1 request every 10 seconds.


    **Rate limits are subject to change. We may adjust these thresholds to ensure stable performance for all customers.**

    '
servers:
- url: https://api.customer.io
  description: The base URL for broadcasts, transactional messages, and data-retrieval APIs. These endpoints use bearer authorization, and require a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
- url: https://api-eu.customer.io
  description: The base URL for broadcasts, transactional messages, and data-retrieval APIs (EU region). These endpoints use bearer authorization, and require a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
tags:
- name: Newsletter Variants
  description: 'A newsletter variant is a translation or an A/B test. You can create, update, or delete variants in newsletters from these endpoints. You can also create a new A/B test group.


    If your newsletters include assets like images or PDFs, host them in your [workspace''s assets](/integrations/api/app/#tag/assets) or at another public URL, and include the URL in your message content.

    '
paths:
  /v1/newsletters/{newsletter_id}/contents:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: newsletter_id
      in: path
      required: true
      description: The identifier of a newsletter.
      schema:
        type: integer
    get:
      summary: List newsletter variants
      operationId: listNewsletterVariants
      security:
      - Bearer-Auth: []
      description: Returns a newsletter's content variants—these are either different languages in a multi-language newsletter or A/B tests.
      tags:
      - Newsletter Variants
      responses:
        '200':
          description: Returns newsletter `content_id`s. Each object represents an individual variant of this newsletter.
          content:
            application/json:
              schema:
                type: object
                properties:
                  contents:
                    type: array
                    items:
                      x-scalar-ignore: true
                      allOf:
                      - x-scalar-ignore: true
                        type: object
                        properties:
                          id:
                            x-scalar-ignore: true
                            type: integer
                            description: The identifier of a newsletter variant—a language in a multi-language newsletter or a test in an A/B test.
                            readOnly: true
                          newsletter_id:
                            x-scalar-ignore: true
                            description: The identifier for a newsletter.
                            type: integer
                            example: 10
                          deduplicate_id:
                            x-scalar-ignore: true
                            type: string
                            readOnly: true
                            description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                            example: 15:1492548073
                          name:
                            type: string
                            description: The name of the variant, if it exists.
                            readOnly: true
                            example: newsletter variant A
                          layout:
                            type: string
                            description: The layout used for the variant, if it exists.
                            example: <html><body>{{ content }}</body></html>
                            readOnly: true
                          body:
                            type: string
                            description: The body of the variant. You cannot modify the body if you created it with our drag-and-drop editor.
                            example: <strong>Hello from the API</strong>
                          body_amp:
                            x-scalar-ignore: true
                            type: string
                            description: AMP-enabled content for your email. If a recipient's email client doesn't support AMP, they receive your `body` content instead. Make sure you're [set up to send AMP](/journeys/channels/email/layouts/amp-for-email/) first.
                          language:
                            x-scalar-ignore: true
                            type: string
                            description: The language variant for your message. If you don't use our [localization feature](/journeys/channels/localization/getting-started), or this is the default message, this value is an empty string.
                            example: fr
                            readOnly: true
                          type:
                            x-scalar-ignore: true
                            description: Channel type for a newsletter or newsletter content variant.
                            type: string
                            enum:
                            - email
                            - webhook
                            - twilio
                            - push
                            - in_app
                            - inbox
                            readOnly: true
                            example: email
                          from:
                            x-scalar-ignore: true
                            type: string
                            description: The address that the message is from, relevant if the action `type` is `email`.
                            readOnly: true
                            example: sentFrom@example.com
                          from_id:
                            x-scalar-ignore: true
                            type: integer
                            description: The identifier of the `from` address, commonly known as the "sender". Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                            example: 1
                          reply_to:
                            x-scalar-ignore: true
                            type: string
                            description: The address that receives replies for the message, if applicable.
                            readOnly: true
                            example: replyto@example.com
                          reply_to_id:
                            x-scalar-ignore: true
                            type:
                            - integer
                            - 'null'
                            description: The identifier for the `reply_to` address, if applicable. Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                            example: 38
                          preprocessor:
                            x-scalar-ignore: true
                            type: string
                            description: If CSS pre-processing is enabled, this key is populated with `premailer`. Note, Juice replaced Premailer as the pre-processor, but you will only see `premailer` as the value.
                            enum:
                            - premailer
                            readOnly: true
                          recipient:
                            x-scalar-ignore: true
                            description: The recipient address for an action.
                            type: string
                            example: '{{customer.email}}'
                          subject:
                            x-scalar-ignore: true
                            type: string
                            description: The subject line for an `email` action.
                            example: Did you get that thing I sent you?
                          cc:
                            x-scalar-ignore: true
                            readOnly: true
                            description: The carbon-copy address(es) for this action.
                            type: string
                          bcc:
                            x-scalar-ignore: true
                            readOnly: true
                            description: The blind-copy address(es) for this action.
                            type: string
                          fake_bcc:
                            x-scalar-ignore: true
                            readOnly: true
                            type: boolean
                            description: 'If true, rather than sending true copies to BCC addresses, Customer.io sends a copy of the message with the subject line containing the recipient address(es).

                              '
                          preheader_text:
                            x-scalar-ignore: true
                            type: string
                            description: '[Also known as "preview text"](/journeys/channels/email/headers/custom-preheader-text/), this is the small block of text shown in an email inbox next to or underneath the subject line.

                              '
                      - type: object
                        properties:
                          headers:
                            x-scalar-ignore: true
                            description: A JSON string containing header objects with `name` and `value`. Names and values must be strings, with no non-ASCII characters or spaces. You can't overwrite reserved headers.
                            type: string
                            format: json
                            example: '[{"name":"X-Mailgun-Tag","value":"my-cool-tag"},{"name":"X-Custom-Header","value":"custom-value"}]'
        '404':
          description: The newsletter you requested does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request GET \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/contents"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"GET\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/contents\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/contents")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Get.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("GET", "/v1/newsletters/%7Bnewsletter_id%7D/contents")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/contents\"\n\n\treq, _ := http.NewRequest(\"GET\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
  /v1/newsletters/{newsletter_id}/contents/{content_id}:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: newsletter_id
      in: path
      required: true
      description: The identifier of a newsletter.
      schema:
        type: integer
    - name: content_id
      in: path
      required: true
      description: 'The identifier of a message in a newsletter. If your newsletter has an A/B test group or includes multiple languages, each variant has its own `content_id`, separate from the `newsletter_id`.


        Use [List variants of a newsletter](#tag/newsletter-variants/listNewsletterVariants) to find the `content_id` associated with the right variant.

        '
      schema:
        type: integer
    get:
      summary: Get a newsletter variant
      operationId: getNewsletterVariant
      security:
      - Bearer-Auth: []
      description: Returns information about a specific variant of a newsletter, where a variant is either a language in a multi-language newsletter or a part of an A/B test.
      tags:
      - Newsletter Variants
      responses:
        '200':
          description: Returns newsletter `content`.
          content:
            application/json:
              schema:
                type: object
                properties:
                  content:
                    x-scalar-ignore: true
                    allOf:
                    - x-scalar-ignore: true
                      type: object
                      properties:
                        id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of a newsletter variant—a language in a multi-language newsletter or a test in an A/B test.
                          readOnly: true
                        newsletter_id:
                          x-scalar-ignore: true
                          description: The identifier for a newsletter.
                          type: integer
                          example: 10
                        deduplicate_id:
                          x-scalar-ignore: true
                          type: string
                          readOnly: true
                          description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                          example: 15:1492548073
                        name:
                          type: string
                          description: The name of the variant, if it exists.
                          readOnly: true
                          example: newsletter variant A
                        layout:
                          type: string
                          description: The layout used for the variant, if it exists.
                          example: <html><body>{{ content }}</body></html>
                          readOnly: true
                        body:
                          type: string
                          description: The body of the variant. You cannot modify the body if you created it with our drag-and-drop editor.
                          example: <strong>Hello from the API</strong>
                        body_amp:
                          x-scalar-ignore: true
                          type: string
                          description: AMP-enabled content for your email. If a recipient's email client doesn't support AMP, they receive your `body` content instead. Make sure you're [set up to send AMP](/journeys/channels/email/layouts/amp-for-email/) first.
                        language:
                          x-scalar-ignore: true
                          type: string
                          description: The language variant for your message. If you don't use our [localization feature](/journeys/channels/localization/getting-started), or this is the default message, this value is an empty string.
                          example: fr
                          readOnly: true
                        type:
                          x-scalar-ignore: true
                          description: Channel type for a newsletter or newsletter content variant.
                          type: string
                          enum:
                          - email
                          - webhook
                          - twilio
                          - push
                          - in_app
                          - inbox
                          readOnly: true
                          example: email
                        from:
                          x-scalar-ignore: true
                          type: string
                          description: The address that the message is from, relevant if the action `type` is `email`.
                          readOnly: true
                          example: sentFrom@example.com
                        from_id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of the `from` address, commonly known as the "sender". Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 1
                        reply_to:
                          x-scalar-ignore: true
                          type: string
                          description: The address that receives replies for the message, if applicable.
                          readOnly: true
                          example: replyto@example.com
                        reply_to_id:
                          x-scalar-ignore: true
                          type:
                          - integer
                          - 'null'
                          description: The identifier for the `reply_to` address, if applicable. Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 38
                        preprocessor:
                          x-scalar-ignore: true
                          type: string
                          description: If CSS pre-processing is enabled, this key is populated with `premailer`. Note, Juice replaced Premailer as the pre-processor, but you will only see `premailer` as the value.
                          enum:
                          - premailer
                          readOnly: true
                        recipient:
                          x-scalar-ignore: true
                          description: The recipient address for an action.
                          type: string
                          example: '{{customer.email}}'
                        subject:
                          x-scalar-ignore: true
                          type: string
                          description: The subject line for an `email` action.
                          example: Did you get that thing I sent you?
                        cc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The carbon-copy address(es) for this action.
                          type: string
                        bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The blind-copy address(es) for this action.
                          type: string
                        fake_bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          type: boolean
                          description: 'If true, rather than sending true copies to BCC addresses, Customer.io sends a copy of the message with the subject line containing the recipient address(es).

                            '
                        preheader_text:
                          x-scalar-ignore: true
                          type: string
                          description: '[Also known as "preview text"](/journeys/channels/email/headers/custom-preheader-text/), this is the small block of text shown in an email inbox next to or underneath the subject line.

                            '
                    - type: object
                      properties:
                        headers:
                          x-scalar-ignore: true
                          description: A JSON string containing header objects with `name` and `value`. Names and values must be strings, with no non-ASCII characters or spaces. You can't overwrite reserved headers.
                          type: string
                          format: json
                          example: '[{"name":"X-Mailgun-Tag","value":"my-cool-tag"},{"name":"X-Custom-Header","value":"custom-value"}]'
        '404':
          description: The newsletter or variant does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request GET \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/contents/{content_id}"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"GET\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/contents/%7Bcontent_id%7D\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/contents/%7Bcontent_id%7D")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Get.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("GET", "/v1/newsletters/%7Bnewsletter_id%7D/contents/%7Bcontent_id%7D")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/contents/%7Bcontent_id%7D\"\n\n\treq, _ := http.NewRequest(\"GET\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
    put:
      summary: Update a newsletter variant
      operationId: updateNewsletterVariant
      security:
      - Bearer-Auth: []
      description: 'Update the content of a newsletter: the default message, a test variant in an A/B test group, or a translation.


        For an email, you can also update the envelope: from address, subject line, etc.


        **NOTE**: You cannot manage content made with the drag-and-drop editor via API, and you cannot use this endpoint to update Design Studio emails. You can, however, [manage Design Studio content with other endpoints](#tag/design-studio).

        '
      tags:
      - Newsletter Variants
      requestBody:
        content:
          application/json:
            schema:
              oneOf:
              - $ref: '#/components/schemas/updateEmailContent'
              - $ref: '#/components/schemas/updateSmsContent'
              - $ref: '#/components/schemas/updatePushContent'
              - $ref: '#/components/schemas/updateWebhookContent'
              - $ref: '#/components/schemas/updateInboxContent'
              discriminator:
                propertyName: type
      responses:
        '200':
          description: Returns the updated newsletter variant.
          content:
            application/json:
              schema:
                type: object
                properties:
                  content:
                    x-scalar-ignore: true
                    allOf:
                    - x-scalar-ignore: true
                      type: object
                      properties:
                        id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of a newsletter variant—a language in a multi-language newsletter or a test in an A/B test.
                          readOnly: true
                        newsletter_id:
                          x-scalar-ignore: true
                          description: The identifier for a newsletter.
                          type: integer
                          example: 10
                        deduplicate_id:
                          x-scalar-ignore: true
                          type: string
                          readOnly: true
                          description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                          example: 15:1492548073
                        name:
                          type: string
                          description: The name of the variant, if it exists.
                          readOnly: true
                          example: newsletter variant A
                        layout:
                          type: string
                          description: The layout used for the variant, if it exists.
                          example: <html><body>{{ content }}</body></html>
                          readOnly: true
                        body:
                          type: string
                          description: The body of the variant. You cannot modify the body if you created it with our drag-and-drop editor.
                          example: <strong>Hello from the API</strong>
                        body_amp:
                          x-scalar-ignore: true
                          type: string
                          description: AMP-enabled content for your email. If a recipient's email client doesn't support AMP, they receive your `body` content instead. Make sure you're [set up to send AMP](/journeys/channels/email/layouts/amp-for-email/) first.
                        language:
                          x-scalar-ignore: true
                          type: string
                          description: The language variant for your message. If you don't use our [localization feature](/journeys/channels/localization/getting-started), or this is the default message, this value is an empty string.
                          example: fr
                          readOnly: true
                        type:
                          x-scalar-ignore: true
                          description: Channel type for a newsletter or newsletter content variant.
                          type: string
                          enum:
                          - email
                          - webhook
                          - twilio
                          - push
                          - in_app
                          - inbox
                          readOnly: true
                          example: email
                        from:
                          x-scalar-ignore: true
                          type: string
                          description: The address that the message is from, relevant if the action `type` is `email`.
                          readOnly: true
                          example: sentFrom@example.com
                        from_id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of the `from` address, commonly known as the "sender". Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 1
                        reply_to:
                          x-scalar-ignore: true
                          type: string
                          description: The address that receives replies for the message, if applicable.
                          readOnly: true
                          example: replyto@example.com
                        reply_to_id:
                          x-scalar-ignore: true
                          type:
                          - integer
                          - 'null'
                          description: The identifier for the `reply_to` address, if applicable. Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 38
                        preprocessor:
                          x-scalar-ignore: true
                          type: string
                          description: If CSS pre-processing is enabled, this key is populated with `premailer`. Note, Juice replaced Premailer as the pre-processor, but you will only see `premailer` as the value.
                          enum:
                          - premailer
                          readOnly: true
                        recipient:
                          x-scalar-ignore: true
                          description: The recipient address for an action.
                          type: string
                          example: '{{customer.email}}'
                        subject:
                          x-scalar-ignore: true
                          type: string
                          description: The subject line for an `email` action.
                          example: Did you get that thing I sent you?
                        cc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The carbon-copy address(es) for this action.
                          type: string
                        bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The blind-copy address(es) for this action.
                          type: string
                        fake_bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          type: boolean
                          description: 'If true, rather than sending true copies to BCC addresses, Customer.io sends a copy of the message with the subject line containing the recipient address(es).

                            '
                        preheader_text:
                          x-scalar-ignore: true
                          type: string
                          description: '[Also known as "preview text"](/journeys/channels/email/headers/custom-preheader-text/), this is the small block of text shown in an email inbox next to or underneath the subject line.

                            '
                    - type: object
                      properties:
                        headers:
                          x-scalar-ignore: true
                          description: A JSON string containing header objects with `name` and `value`. Names and values must be strings, with no non-ASCII characters or spaces. You can't overwrite reserved headers.
                          type: string
                          format: json
                          example: '[{"name":"X-Mailgun-Tag","value":"my-cool-tag"},{"name":"X-Custom-Header","value":"custom-value"}]'
        '400':
          description: The request is malformed.
        '404':
          description: The newsletter or variant does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: json
        label: JSON
        source: '{}'
      - lang: Shell + Curl
        source: "curl --request PUT \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/contents/{content_id} \\\n  --header 'content-type: application/json' \\\n  --data '{\"body\":\"string\",\"body_amp\":\"string\",\"body_plain\":\"string\",\"subject\":\"Did you get that thing I sent you?\",\"preheader_text\":\"string\",\"from_id\":1,\"reply_to_id\":38,\"recipient\":\"string\"}'"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"PUT\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/contents/%7Bcontent_id%7D\",\n  \"headers\": {\n    \"content-type\": \"application/json\"\n  }\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.write(JSON.stringify({\n  body: 'string',\n  body_amp: 'string',\n  body_plain: 'string',\n  subject: 'Did you get that thing I sent you?',\n  preheader_text: 'string',\n  from_id: 1,\n  reply_to_id: 38,\n  recipient: 'string'\n}));\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/contents/%7Bcontent_id%7D")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Put.new(url)

          request["content-type"] = ''application/json''

          request.body = "{\"body\":\"string\",\"body_amp\":\"string\",\"body_plain\":\"string\",\"subject\":\"Did you get that thing I sent you?\",\"preheader_text\":\"string\",\"from_id\":1,\"reply_to_id\":38,\"recipient\":\"string\"}"


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          payload = "{\"body\":\"string\",\"body_amp\":\"string\",\"body_plain\":\"string\",\"subject\":\"Did you get that thing I sent you?\",\"preheader_text\":\"string\",\"from_id\":1,\"reply_to_id\":38,\"recipient\":\"string\"}"


          headers = { ''content-type'': "application/json" }


          conn.request("PUT", "/v1/newsletters/%7Bnewsletter_id%7D/contents/%7Bcontent_id%7D", payload, headers)


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"strings\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/contents/%7Bcontent_id%7D\"\n\n\tpayload := strings.NewReader(\"{\\\"body\\\":\\\"string\\\",\\\"body_amp\\\":\\\"string\\\",\\\"body_plain\\\":\\\"string\\\",\\\"subject\\\":\\\"Did you get that thing I sent you?\\\",\\\"preheader_text\\\":\\\"string\\\",\\\"from_id\\\":1,\\\"reply_to_id\\\":38,\\\"recipient\\\":\\\"string\\\"}\")\n\n\treq, _ := http.NewRequest(\"PUT\", url, payload)\n\n\treq.Header.Add(\"content-type\", \"application/json\")\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
  /v1/newsletters/{newsletter_id}/language:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: newsletter_id
      in: path
      required: true
      description: The identifier of a newsletter.
      schema:
        type: integer
    post:
      summary: Add a translation to a newsletter
      operationId: createNewsletterLanguageVariant
      security:
      - Bearer-Auth: []
      description: 'Add a language variant to a newsletter.


        If you omit optional fields, the values from the default template are copied over untranslated. Make sure you translate all aspects of your default template.


        You can''t add language variants to a newsletter that has already been sent. You can''t manage emails created with the drag-and-drop editor or Design Studio via this endpoint—use [Create an email translation](#tag/design-studio/createEmailTranslation) for Design Studio emails.


        If the newsletter has A/B tests, use [Add a translation to a newsletter test group](#operation/createNewsletterTestLanguageVariant) instead.

        '
      tags:
      - Newsletter Variants
      requestBody:
        required: true
        content:
          application/json:
            schema:
              description: Add a language variant to a newsletter. The payload the endpoint accepts depends on the parent newsletter's channel type.
              oneOf:
              - title: Email
                description: Add a language variant to an email newsletter. Requires `language`, `subject`, and `body`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  required:
                  - subject
                  - body
                  properties:
                    subject:
                      type: string
                      description: The subject line for the variant.
                      example: ¡Hola, {{ customer.name }}!
                    preheader_text:
                      type: string
                      description: The preheader text for the email variant.
                      example: Mira nuestras últimas novedades
                    body:
                      type: string
                      description: The HTML body content for the variant.
                      example: <html><body><h1>¡Hola!</h1></body></html>
                    body_plain:
                      type: string
                      description: The plaintext body content for the variant.
                    body_amp:
                      type: string
                      description: The AMP HTML body content for the variant.
              - title: SMS
                description: Add a language variant to an SMS newsletter. Requires `language` and `body`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  required:
                  - body
                  properties:
                    body:
                      type: string
                      description: The body content of the SMS message.
                      example: ¡Hola {{ customer.first_name }}! Tu pedido ha sido enviado.
              - title: Push
                description: Add a language variant to a push notification newsletter. Requires `language` and at least one of `subject` or `body`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  properties:
                    subject:
                      type: string
                      description: The title of the push notification.
                      example: ¡Oferta por tiempo limitado!
                    body:
                      type: string
                      description: The body content of the push notification.
                      example: Obtén 30% de descuento en todo.
              - title: Webhook
                description: Add a language variant to a webhook newsletter. Requires `language` and `body`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  required:
                  - body
                  properties:
                    body:
                      type: string
                      description: The body content of the webhook request.
                      example: '{"channel":"#marketing","text":"Boletín enviado a {{ customer.email }}"}'
              - title: Inbox message
                description: Add a language variant to an inbox message newsletter. Requires `language` and `body_json`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  required:
                  - body_json
                  properties:
                    body_json:
                      type: string
                      description: JSON body content for the inbox message variant. Learn more about [message settings](/journeys/channels/in-app/inbox/send-inbox/) in our docs.
                      example: '{"topics": ["general", "updates"], "type": "notification", "expiration": {"type": "relative", "value": "30", "unit": "days"}, "properties": {"title": "Welcome!", "message": "Thanks for signing up", "link": "https://customer.io"}}'
      responses:
        '200':
          description: Returns the updated newsletter, including new `content_ids`.
          content:
            application/json:
              schema:
                type: object
                properties:
                  newsletter:
                    x-scalar-ignore: true
                    type: object
                    properties:
                      id:
                        x-scalar-ignore: true
                        description: The identifier for a newsletter.
                        type: integer
                        example: 10
                      deduplicate_id:
                        x-scalar-ignore: true
                        type: string
                        readOnly: true
                        description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                        example: 15:1492548073
                      content_ids:
                        type: array
                        description: A list of message variants in a newsletter, where a variant is a translation or A/B test.
                        items:
                          type: integer
                      name:
                        type: string
                        description: The name of the newsletter. Must be 190 characters or less.
                        readOnly: true
                      sent_at:
                        type: integer
                        format: unix timestamp
                        description: The last time the newsletter was sent.
                      created:
                        x-scalar-ignore: true
                        type: integer
                        format: unix timestamp
                        description: The date time when the referenced ID was created.
                        example: 1552341937
                        readOnly: true
                      updated:
                        x-scalar-ignore: true
                        type: integer
                        format: unix timestamp
                        description: The date time when the referenced ID was last updated.
                        example: 1552341937
                        readOnly: true
                      type:
                        x-scalar-ignore: true
                        description: Channel type for a newsletter or newsletter content variant.
                        type: string
                        enum:
                        - email
                        - webhook
                        - twilio
                        - push
                        - in_app
                        - inbox
                        readOnly: true
                        example: email
                      tags:
                        type: array
                        description: An array of tags associated with the newsletter.
                        items:
                          type: string
                      recipient_segment_ids:
                        description: If the recipient conditions included segments, this returns a list of those segment ids.
                        type: array
                        items:
                          type: integer
                      subscription_topic_id:
                        type: integer
                        description: If you enabled a [subscription center](/journeys/channels/subscriptions/center/) on your workspace, this returns the id of the subscription preference you set.
                    example:
                      id: 128275
                      deduplicate_id: 128275:1484870424
                      type: email
                      content_ids:
                      - 45
                      name: Weekly Product Update
                      sent_at: 1481653929
                      created: 1481653919
                      updated: 1481653929
                      recipient_segment_ids:
                      - 42
                      - 99
                      tags:
                      - Product Updates
                      subscription_topic_id: 5
        '400':
          description: 'The request is invalid. Possible reasons include: the newsletter has already been sent, the newsletter has multiple test groups ([add a translation to a test group](#tag/newsletter-variants/createNewsletterTestLanguageVariant) instead), or the newsletter uses Design Studio or drag-and-drop editors.

            '
        '404':
          description: The newsletter does not exist.
        '422':
          description: 'Validation error. Possible reasons: `language` is missing, required content fields are missing for the channel type, or the language variant already exists.

            '
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: json
        label: JSON
        source: "{\n  \"language\": \"es\",\n  \"subject\": \"¡Hola, {{ customer.name }}!\",\n  \"body\": \"<html><body><h1>¡Hola!</h1></body></html>\"\n}"
      - lang: Shell + Curl
        source: "curl --request POST \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/language \\\n  --header 'content-type: application/json' \\\n  --data '{\"language\":\"es\",\"subject\":\"¡Hola, {{ customer.name }}!\",\"preheader_text\":\"Mira nuestras últimas novedades\",\"body\":\"<html><body><h1>¡Hola!</h1></body></html>\",\"body_plain\":\"string\",\"body_amp\":\"string\"}'"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"POST\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/language\",\n  \"headers\": {\n    \"content-type\": \"application/json\"\n  }\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.write(JSON.stringify({\n  language: 'es',\n  subject: '¡Hola, {{ customer.name }}!',\n  preheader_text: 'Mira nuestras últimas novedades',\n  body: '<html><body><h1>¡Hola!</h1></body></html>',\n  body_plain: 'string',\n  body_amp: 'string'\n}));\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/language")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Post.new(url)

          request["content-type"] = ''application/json''

          request.body = "{\"language\":\"es\",\"subject\":\"¡Hola, {{ customer.name }}!\",\"preheader_text\":\"Mira nuestras últimas novedades\",\"body\":\"<html><body><h1>¡Hola!</h1></body></html>\",\"body_plain\":\"string\",\"body_amp\":\"string\"}"


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          payload = "{\"language\":\"es\",\"subject\":\"¡Hola, {{ customer.name }}!\",\"preheader_text\":\"Mira nuestras últimas novedades\",\"body\":\"<html><body><h1>¡Hola!</h1></body></html>\",\"body_plain\":\"string\",\"body_amp\":\"string\"}"


          headers = { ''content-type'': "application/json" }


          conn.request("POST", "/v1/newsletters/%7Bnewsletter_id%7D/language", payload, headers)


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"strings\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/language\"\n\n\tpayload := strings.NewReader(\"{\\\"language\\\":\\\"es\\\",\\\"subject\\\":\\\"¡Hola, {{ customer.name }}!\\\",\\\"preheader_text\\\":\\\"Mira nuestras últimas novedades\\\",\\\"body\\\":\\\"<html><body><h1>¡Hola!</h1></body></html>\\\",\\\"body_plain\\\":\\\"string\\\",\\\"body_amp\\\":\\\"string\\\"}\")\n\n\treq, _ := http.NewRequest(\"POST\", url, payload)\n\n\treq.Header.Add(\"content-type\", \"application/json\")\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
  /v1/newsletters/{newsletter_id}/language/{language}:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: newsletter_id
      in: path
      required: true
      description: The identifier of a newsletter.
      schema:
        type: integer
    - name: language
      in: path
      required: true
      description: A [language tag](/journeys/channels/subscriptions/unsubscribe-faqs/#currently-supported-languages) of a language variant. If you don't provide a language (an empty string), we'll use your default language. If the language variant does not exist, we'll return an error.
      schema:
        type: string
    get:
      summary: Get a newsletter translation
      operationId: getNewsletterVariantTranslation
      security:
      - Bearer-Auth: []
      description: Returns information about a specific language variant of a newsletter. If your newsletter includes A/B tests, use [Get a translation in a newsletter test group](/api/app/#operation/getNewsletterVariantTranslationTest).
      tags:
      - Newsletter Variants
      responses:
        '200':
          description: Returns newsletter `content` for a language variant.
          content:
            application/json:
              schema:
                type: object
                properties:
                  content:
                    x-scalar-ignore: true
                    allOf:
                    - x-scalar-ignore: true
                      type: object
                      properties:
                        id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of a newsletter variant—a language in a multi-language newsletter or a test in an A/B test.
                          readOnly: true
                        newsletter_id:
                          x-scalar-ignore: true
                          description: The identifier for a newsletter.
                          type: integer
                          example: 10
                        deduplicate_id:
                          x-scalar-ignore: true
                          type: string
                          readOnly: true
                          description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                          example: 15:1492548073
                        name:
                          type: string
                          description: The name of the variant, if it exists.
                          readOnly: true
                          example: newsletter variant A
                        layout:
                          type: string
                          description: The layout used for the variant, if it exists.
                          example: <html><body>{{ content }}</body></html>
                          readOnly: true
                        body:
                          type: string
                          description: The body of the variant. You cannot modify the body if you created it with our drag-and-drop editor.
                          example: <strong>Hello from the API</strong>
                        body_amp:
                          x-scalar-ignore: true
                          type: string
                          description: AMP-enabled content for your email. If a recipient's email client doesn't support AMP, they receive your `body` content instead. Make sure you're [set up to send AMP](/journeys/channels/email/layouts/amp-for-email/) first.
                        language:
                          x-scalar-ignore: true
                          type: string
                          description: The language variant for your message. If you don't use our [localization feature](/journeys/channels/localization/getting-started), or this is the default message, this value is an empty string.
                          example: fr
                          readOnly: true
                        type:
                          x-scalar-ignore: true
                          description: Channel type for a newsletter or newsletter content variant.
                          type: string
                          enum:
                          - email
                          - webhook
                          - twilio
                          - push
                          - in_app
                          - inbox
                          readOnly: true
                          example: email
                        from:
                          x-scalar-ignore: true
                          type: string
                          description: The address that the message is from, relevant if the action `type` is `email`.
                          readOnly: true
                          example: sentFrom@example.com
                        from_id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of the `from` address, commonly known as the "sender". Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 1
                        reply_to:
                          x-scalar-ignore: true
                          type: string
                          description: The address that receives replies for the message, if applicable.
                          readOnly: true
                          example: replyto@example.com
                        reply_to_id:
                          x-scalar-ignore: true
                          type:
                          - integer
                          - 'null'
                          description: The identifier for the `reply_to` address, if applicable. Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 38
                        preprocessor:
                          x-scalar-ignore: true
                          type: string
                          description: If CSS pre-processing is enabled, this key is populated with `premailer`. Note, Juice replaced Premailer as the pre-processor, but you will only see `premailer` as the value.
                          enum:
                          - premailer
                          readOnly: true
                        recipient:
                          x-scalar-ignore: true
                          description: The recipient address for an action.
                          type: string
                          example: '{{customer.email}}'
                        subject:
                          x-scalar-ignore: true
                          type: string
                          description: The subject line for an `email` action.
                          example: Did you get that thing I sent you?
                        cc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The carbon-copy address(es) for this action.
                          type: string
                        bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The blind-copy address(es) for this action.
                          type: string
                        fake_bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          type: boolean
                          description: 'If true, rather than sending true copies to BCC addresses, Customer.io sends a copy of the message with the subject line containing the recipient address(es).

                            '
                        preheader_text:
                          x-scalar-ignore: true
                          type: string
                          description: '[Also known as "preview text"](/journeys/channels/email/headers/custom-preheader-text/), this is the small block of text shown in an email inbox next to or underneath the subject line.

                            '
                    - type: object
                      properties:
                        headers:
                          x-scalar-ignore: true
                          description: A JSON string containing header objects with `name` and `value`. Names and values must be strings, with no non-ASCII characters or spaces. You can't overwrite reserved headers.
                          type: string
                          format: json
                          example: '[{"name":"X-Mailgun-Tag","value":"my-cool-tag"},{"name":"X-Custom-Header","value":"custom-value"}]'
        '400':
          description: The `language` does not exist.
        '404':
          description: The newsletter or variant does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request GET \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/language/{language}"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"GET\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Get.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("GET", "/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D\"\n\n\treq, _ := http.NewRequest(\"GET\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
    put:
      summary: Update a translation of a newsletter
      operationId: updateNewsletterVariantTranslation
      security:
      - Bearer-Auth: []
      description: 'Update the translation of a newsletter variant. If your newsletter includes A/B tests, use [Update a translation in a newsletter test group](/api/app/#operation/updateNewsletterTestTranslation).


        **NOTE**: You cannot manage content made with Design Studio with this endpoint. Use the [Design Studio APIs](#tag/design-studio) instead.

        '
      tags:
      - Newsletter Variants
      requestBody:
        content:
          application/json:
            schema:
              oneOf:
              - $ref: '#/components/schemas/updateEmailContent'
              - $ref: '#/components/schemas/updateSmsContent'
              - $ref: '#/components/schemas/updatePushContent'
              - $ref: '#/components/schemas/updateWebhookContent'
              - $ref: '#/components/schemas/updateInboxContent'
              discriminator:
                propertyName: type
      responses:
        '200':
          description: Returns the updated newsletter variant.
          content:
            application/json:
              schema:
                type: object
                properties:
                  content:
                    x-scalar-ignore: true
                    allOf:
                    - x-scalar-ignore: true
                      type: object
                      properties:
                        id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of a newsletter variant—a language in a multi-language newsletter or a test in an A/B test.
                          readOnly: true
                        newsletter_id:
                          x-scalar-ignore: true
                          description: The identifier for a newsletter.
                          type: integer
                          example: 10
                        deduplicate_id:
                          x-scalar-ignore: true
                          type: string
                          readOnly: true
                          description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                          example: 15:1492548073
                        name:
                          type: string
                          description: The name of the variant, if it exists.
                          readOnly: true
                          example: newsletter variant A
                        layout:
                          type: string
                          description: The layout used for the variant, if it exists.
                          example: <html><body>{{ content }}</body></html>
                          readOnly: true
                        body:
                          type: string
                          description: The body of the variant. You cannot modify the body if you created it with our drag-and-drop editor.
                          example: <strong>Hello from the API</strong>
                        body_amp:
                          x-scalar-ignore: true
                          type: string
                          description: AMP-enabled content for your email. If a recipient's email client doesn't support AMP, they receive your `body` content instead. Make sure you're [set up to send AMP](/journeys/channels/email/layouts/amp-for-email/) first.
                        language:
                          x-scalar-ignore: true
                          type: string
                          description: The language variant for your message. If you don't use our [localization feature](/journeys/channels/localization/getting-started), or this is the default message, this value is an empty string.
                          example: fr
                          readOnly: true
                        type:
                          x-scalar-ignore: true
                          description: Channel type for a newsletter or newsletter content variant.
                          type: string
                          enum:
                          - email
                          - webhook
                          - twilio
                          - push
                          - in_app
                          - inbox
                          readOnly: true
                          example: email
                        from:
                          x-scalar-ignore: true
                          type: string
                          description: The address that the message is from, relevant if the action `type` is `email`.
                          readOnly: true
                          example: sentFrom@example.com
                        from_id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of the `from` address, commonly known as the "sender". Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 1
                        reply_to:
                          x-scalar-ignore: true
                          type: string
                          description: The address that receives replies for the message, if applicable.
                          readOnly: true
                          example: replyto@example.com
                        reply_to_id:
                          x-scalar-ignore: true
                          type:
                          - integer
                          - 'null'
                          description: The identifier for the `reply_to` address, if applicable. Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 38
                        preprocessor:
                          x-scalar-ignore: true
                          type: string
                          description: If CSS pre-processing is enabled, this key is populated with `premailer`. Note, Juice replaced Premailer as the pre-processor, but you will only see `premailer` as the value.
                          enum:
                          - premailer
                          readOnly: true
                        recipient:
                          x-scalar-ignore: true
                          description: The recipient address for an action.
                          type: string
                          example: '{{customer.email}}'
                        subject:
                          x-scalar-ignore: true
                          type: string
                          description: The subject line for an `email` action.
                          example: Did you get that thing I sent you?
                        cc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The carbon-copy address(es) for this action.
                          type: string
                        bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The blind-copy address(es) for this action.
                          type: string
                        fake_bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          type: boolean
                          description: 'If true, rather than sending true copies to BCC addresses, Customer.io sends a copy of the message with the subject line containing the recipient address(es).

                            '
                        preheader_text:
                          x-scalar-ignore: true
                          type: string
                          description: '[Also known as "preview text"](/journeys/channels/email/headers/custom-preheader-text/), this is the small block of text shown in an email inbox next to or underneath the subject line.

                            '
                    - type: object
                      properties:
                        headers:
                          x-scalar-ignore: true
                          description: A JSON string containing header objects with `name` and `value`. Names and values must be strings, with no non-ASCII characters or spaces. You can't overwrite reserved headers.
                          type: string
                          format: json
                          example: '[{"name":"X-Mailgun-Tag","value":"my-cool-tag"},{"name":"X-Custom-Header","value":"custom-value"}]'
        '400':
          description: The `language` does not exist.
        '404':
          description: The newsletter or variant does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: json
        label: JSON
        source: '{}'
      - lang: Shell + Curl
        source: "curl --request PUT \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/language/{language} \\\n  --header 'content-type: application/json' \\\n  --data '{\"body\":\"string\",\"body_amp\":\"string\",\"body_plain\":\"string\",\"subject\":\"Did you get that thing I sent you?\",\"preheader_text\":\"string\",\"from_id\":1,\"reply_to_id\":38,\"recipient\":\"string\"}'"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"PUT\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D\",\n  \"headers\": {\n    \"content-type\": \"application/json\"\n  }\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.write(JSON.stringify({\n  body: 'string',\n  body_amp: 'string',\n  body_plain: 'string',\n  subject: 'Did you get that thing I sent you?',\n  preheader_text: 'string',\n  from_id: 1,\n  reply_to_id: 38,\n  recipient: 'string'\n}));\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Put.new(url)

          request["content-type"] = ''application/json''

          request.body = "{\"body\":\"string\",\"body_amp\":\"string\",\"body_plain\":\"string\",\"subject\":\"Did you get that thing I sent you?\",\"preheader_text\":\"string\",\"from_id\":1,\"reply_to_id\":38,\"recipient\":\"string\"}"


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          payload = "{\"body\":\"string\",\"body_amp\":\"string\",\"body_plain\":\"string\",\"subject\":\"Did you get that thing I sent you?\",\"preheader_text\":\"string\",\"from_id\":1,\"reply_to_id\":38,\"recipient\":\"string\"}"


          headers = { ''content-type'': "application/json" }


          conn.request("PUT", "/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D", payload, headers)


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"strings\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D\"\n\n\tpayload := strings.NewReader(\"{\\\"body\\\":\\\"string\\\",\\\"body_amp\\\":\\\"string\\\",\\\"body_plain\\\":\\\"string\\\",\\\"subject\\\":\\\"Did you get that thing I sent you?\\\",\\\"preheader_text\\\":\\\"string\\\",\\\"from_id\\\":1,\\\"reply_to_id\\\":38,\\\"recipient\\\":\\\"string\\\"}\")\n\n\treq, _ := http.NewRequest(\"PUT\", url, payload)\n\n\treq.Header.Add(\"content-type\", \"application/json\")\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
    delete:
      summary: Delete a translation of a newsletter
      operationId: deleteNewsletterLanguageVariant
      security:
      - Bearer-Auth: []
      description: 'Delete a specific language variant of a newsletter. You cannot delete the default language variant. If your newsletter has already been sent, you cannot delete language variants.


        If your newsletter includes A/B tests, use [Delete a translation in a newsletter test group](#operation/deleteNewsletterTestLanguageVariant).

        '
      tags:
      - Newsletter Variants
      responses:
        '204':
          description: Success. No content.
        '400':
          description: You cannot delete the default language variant, or the newsletter has already been sent.
        '404':
          description: The newsletter or language variant does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request DELETE \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/language/{language}"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"DELETE\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Delete.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("DELETE", "/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/language/%7Blanguage%7D\"\n\n\treq, _ := http.NewRequest(\"DELETE\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
  /v1/newsletters/{newsletter_id}/test_groups:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: newsletter_id
      in: path
      required: true
      description: The identifier of a newsletter.
      schema:
        type: integer
    get:
      summary: List a newsletter's A/B test groups
      operationId: getNewsletterTestGroups
      security:
      - Bearer-Auth: []
      description: Returns information about each test group in a newsletter, including content ids for each group.
      tags:
      - Newsletter Variants
      responses:
        '200':
          description: Returns metadata for each test group in a newsletter.
          content:
            application/json:
              schema:
                type: object
                properties:
                  test_groups:
                    type: array
                    description: Each object represents one of the test groups.
                    items:
                      type: object
                      properties:
                        id:
                          type: integer
                          description: The ID of the A/B test group.
                        name:
                          type: string
                          description: The name of the A/B test group.
                        label:
                          type: string
                          description: The name of the variant.
                        winner:
                          type: boolean
                          description: Whether this variant is the winner of the test.
                        content_ids:
                          description: A list of content_ids for each variant in the test group.
                          type: array
                          items:
                            type: string
                example:
                  test_groups:
                  - id: 0
                    name: A
                    label: test 1
                    winner: false
                    content_ids:
                    - 25
                    - 26
                  - id: 2
                    name: B
                    label: test 2
                    winner: false
                    content_ids:
                    - 27
                    - 28
        '404':
          description: The newsletter or variant does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request GET \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/test_groups"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"GET\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/test_groups\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_groups")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Get.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("GET", "/v1/newsletters/%7Bnewsletter_id%7D/test_groups")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_groups\"\n\n\treq, _ := http.NewRequest(\"GET\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
    post:
      summary: Create an A/B test group for a newsletter
      operationId: createNewsletterTestGroup
      security:
      - Bearer-Auth: []
      description: 'Create a new A/B test group for a newsletter. This duplicates the existing newsletter content into a new test group, allowing you to test different versions of your message.


        This endpoint does not require a request body. The new test group is created as a copy of the existing content.


        You cannot add test groups to a newsletter that has already been sent.

        '
      tags:
      - Newsletter Variants
      requestBody:
        required: false
        content:
          application/json:
            schema:
              type: object
              description: No request body is required.
      responses:
        '200':
          description: Returns the updated newsletter with the new test group's content IDs.
          content:
            application/json:
              schema:
                type: object
                properties:
                  newsletter:
                    x-scalar-ignore: true
                    type: object
                    properties:
                      id:
                        x-scalar-ignore: true
                        description: The identifier for a newsletter.
                        type: integer
                        example: 10
                      deduplicate_id:
                        x-scalar-ignore: true
                        type: string
                        readOnly: true
                        description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                        example: 15:1492548073
                      content_ids:
                        type: array
                        description: A list of message variants in a newsletter, where a variant is a translation or A/B test.
                        items:
                          type: integer
                      name:
                        type: string
                        description: The name of the newsletter. Must be 190 characters or less.
                        readOnly: true
                      sent_at:
                        type: integer
                        format: unix timestamp
                        description: The last time the newsletter was sent.
                      created:
                        x-scalar-ignore: true
                        type: integer
                        format: unix timestamp
                        description: The date time when the referenced ID was created.
                        example: 1552341937
                        readOnly: true
                      updated:
                        x-scalar-ignore: true
                        type: integer
                        format: unix timestamp
                        description: The date time when the referenced ID was last updated.
                        example: 1552341937
                        readOnly: true
                      type:
                        x-scalar-ignore: true
                        description: Channel type for a newsletter or newsletter content variant.
                        type: string
                        enum:
                        - email
                        - webhook
                        - twilio
                        - push
                        - in_app
                        - inbox
                        readOnly: true
                        example: email
                      tags:
                        type: array
                        description: An array of tags associated with the newsletter.
                        items:
                          type: string
                      recipient_segment_ids:
                        description: If the recipient conditions included segments, this returns a list of those segment ids.
                        type: array
                        items:
                          type: integer
                      subscription_topic_id:
                        type: integer
                        description: If you enabled a [subscription center](/journeys/channels/subscriptions/center/) on your workspace, this returns the id of the subscription preference you set.
                    example:
                      id: 128275
                      deduplicate_id: 128275:1484870424
                      type: email
                      content_ids:
                      - 45
                      name: Weekly Product Update
                      sent_at: 1481653929
                      created: 1481653919
                      updated: 1481653929
                      recipient_segment_ids:
                      - 42
                      - 99
                      tags:
                      - Product Updates
                      subscription_topic_id: 5
        '400':
          description: The newsletter has already been sent. You cannot add test groups to a sent newsletter.
        '404':
          description: The newsletter does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: json
        label: JSON
        source: '{}'
      - lang: Shell + Curl
        source: "curl --request POST \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/test_groups \\\n  --header 'content-type: application/json' \\\n  --data '{}'"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"POST\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/test_groups\",\n  \"headers\": {\n    \"content-type\": \"application/json\"\n  }\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.write(JSON.stringify({}));\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_groups")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Post.new(url)

          request["content-type"] = ''application/json''

          request.body = "{}"


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          payload = "{}"


          headers = { ''content-type'': "application/json" }


          conn.request("POST", "/v1/newsletters/%7Bnewsletter_id%7D/test_groups", payload, headers)


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"strings\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_groups\"\n\n\tpayload := strings.NewReader(\"{}\")\n\n\treq, _ := http.NewRequest(\"POST\", url, payload)\n\n\treq.Header.Add(\"content-type\", \"application/json\")\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
  /v1/newsletters/{newsletter_id}/test_group/{test_group_id}/language:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: newsletter_id
      in: path
      required: true
      description: The identifier of a newsletter.
      schema:
        type: integer
    - name: test_group_id
      in: path
      description: The ID of the A/B test group.
      required: true
      schema:
        type: string
    post:
      summary: Add a translation to a newsletter test group
      operationId: createNewsletterTestLanguageVariant
      security:
      - Bearer-Auth: []
      description: 'Add a language variant to a specific A/B test group in a newsletter. The new variant is a copy of the default template in the test group with the content you provide. The payload the endpoint accepts depends on the parent newsletter''s channel type: if the newsletter is an email, the payload will be an email variant; if the newsletter is an SMS, the payload will be an SMS variant.


        You cannot add language variants to a newsletter that has already been sent, or to newsletters created with the drag-and-drop editor or Design Studio.

        '
      tags:
      - Newsletter Variants
      requestBody:
        required: true
        content:
          application/json:
            schema:
              description: Add a language variant to a newsletter. The payload the endpoint accepts depends on the parent newsletter's channel type.
              oneOf:
              - title: Email
                description: Add a language variant to an email newsletter. Requires `language`, `subject`, and `body`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  required:
                  - subject
                  - body
                  properties:
                    subject:
                      type: string
                      description: The subject line for the variant.
                      example: ¡Hola, {{ customer.name }}!
                    preheader_text:
                      type: string
                      description: The preheader text for the email variant.
                      example: Mira nuestras últimas novedades
                    body:
                      type: string
                      description: The HTML body content for the variant.
                      example: <html><body><h1>¡Hola!</h1></body></html>
                    body_plain:
                      type: string
                      description: The plaintext body content for the variant.
                    body_amp:
                      type: string
                      description: The AMP HTML body content for the variant.
              - title: SMS
                description: Add a language variant to an SMS newsletter. Requires `language` and `body`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  required:
                  - body
                  properties:
                    body:
                      type: string
                      description: The body content of the SMS message.
                      example: ¡Hola {{ customer.first_name }}! Tu pedido ha sido enviado.
              - title: Push
                description: Add a language variant to a push notification newsletter. Requires `language` and at least one of `subject` or `body`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  properties:
                    subject:
                      type: string
                      description: The title of the push notification.
                      example: ¡Oferta por tiempo limitado!
                    body:
                      type: string
                      description: The body content of the push notification.
                      example: Obtén 30% de descuento en todo.
              - title: Webhook
                description: Add a language variant to a webhook newsletter. Requires `language` and `body`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  required:
                  - body
                  properties:
                    body:
                      type: string
                      description: The body content of the webhook request.
                      example: '{"channel":"#marketing","text":"Boletín enviado a {{ customer.email }}"}'
              - title: Inbox message
                description: Add a language variant to an inbox message newsletter. Requires `language` and `body_json`.
                allOf:
                - type: object
                  required:
                  - language
                  properties:
                    language:
                      type: string
                      description: The [language tag](/journeys/channels/localization/attribute/#supported-languages) for the new variant, e.g. `es`, `fr`, `de`.
                      example: es
                - type: object
                  required:
                  - body_json
                  properties:
                    body_json:
                      type: string
                      description: JSON body content for the inbox message variant. Learn more about [message settings](/journeys/channels/in-app/inbox/send-inbox/) in our docs.
                      example: '{"topics": ["general", "updates"], "type": "notification", "expiration": {"type": "relative", "value": "30", "unit": "days"}, "properties": {"title": "Welcome!", "message": "Thanks for signing up", "link": "https://customer.io"}}'
      responses:
        '200':
          description: Returns the updated newsletter, including new `content_ids`.
          content:
            application/json:
              schema:
                type: object
                properties:
                  newsletter:
                    x-scalar-ignore: true
                    type: object
                    properties:
                      id:
                        x-scalar-ignore: true
                        description: The identifier for a newsletter.
                        type: integer
                        example: 10
                      deduplicate_id:
                        x-scalar-ignore: true
                        type: string
                        readOnly: true
                        description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                        example: 15:1492548073
                      content_ids:
                        type: array
                        description: A list of message variants in a newsletter, where a variant is a translation or A/B test.
                        items:
                          type: integer
                      name:
                        type: string
                        description: The name of the newsletter. Must be 190 characters or less.
                        readOnly: true
                      sent_at:
                        type: integer
                        format: unix timestamp
                        description: The last time the newsletter was sent.
                      created:
                        x-scalar-ignore: true
                        type: integer
                        format: unix timestamp
                        description: The date time when the referenced ID was created.
                        example: 1552341937
                        readOnly: true
                      updated:
                        x-scalar-ignore: true
                        type: integer
                        format: unix timestamp
                        description: The date time when the referenced ID was last updated.
                        example: 1552341937
                        readOnly: true
                      type:
                        x-scalar-ignore: true
                        description: Channel type for a newsletter or newsletter content variant.
                        type: string
                        enum:
                        - email
                        - webhook
                        - twilio
                        - push
                        - in_app
                        - inbox
                        readOnly: true
                        example: email
                      tags:
                        type: array
                        description: An array of tags associated with the newsletter.
                        items:
                          type: string
                      recipient_segment_ids:
                        description: If the recipient conditions included segments, this returns a list of those segment ids.
                        type: array
                        items:
                          type: integer
                      subscription_topic_id:
                        type: integer
                        description: If you enabled a [subscription center](/journeys/channels/subscriptions/center/) on your workspace, this returns the id of the subscription preference you set.
                    example:
                      id: 128275
                      deduplicate_id: 128275:1484870424
                      type: email
                      content_ids:
                      - 45
                      name: Weekly Product Update
                      sent_at: 1481653929
                      created: 1481653919
                      updated: 1481653929
                      recipient_segment_ids:
                      - 42
                      - 99
                      tags:
                      - Product Updates
                      subscription_topic_id: 5
        '400':
          description: 'The request is invalid. Possible reasons include: the newsletter has already been sent, the test group does not exist, or the newsletter uses Design Studio or drag-and-drop editor.

            '
        '404':
          description: The newsletter does not exist.
        '422':
          description: 'Validation error. Possible reasons: `language` is missing, required content fields are missing for the channel type, or the language variant already exists.

            '
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: json
        label: JSON
        source: "{\n  \"language\": \"es\",\n  \"subject\": \"¡Hola, {{ customer.name }}!\",\n  \"body\": \"<html><body><h1>¡Hola!</h1></body></html>\"\n}"
      - lang: Shell + Curl
        source: "curl --request POST \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/test_group/{test_group_id}/language \\\n  --header 'content-type: application/json' \\\n  --data '{\"language\":\"es\",\"subject\":\"¡Hola, {{ customer.name }}!\",\"preheader_text\":\"Mira nuestras últimas novedades\",\"body\":\"<html><body><h1>¡Hola!</h1></body></html>\",\"body_plain\":\"string\",\"body_amp\":\"string\"}'"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"POST\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language\",\n  \"headers\": {\n    \"content-type\": \"application/json\"\n  }\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.write(JSON.stringify({\n  language: 'es',\n  subject: '¡Hola, {{ customer.name }}!',\n  preheader_text: 'Mira nuestras últimas novedades',\n  body: '<html><body><h1>¡Hola!</h1></body></html>',\n  body_plain: 'string',\n  body_amp: 'string'\n}));\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Post.new(url)

          request["content-type"] = ''application/json''

          request.body = "{\"language\":\"es\",\"subject\":\"¡Hola, {{ customer.name }}!\",\"preheader_text\":\"Mira nuestras últimas novedades\",\"body\":\"<html><body><h1>¡Hola!</h1></body></html>\",\"body_plain\":\"string\",\"body_amp\":\"string\"}"


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          payload = "{\"language\":\"es\",\"subject\":\"¡Hola, {{ customer.name }}!\",\"preheader_text\":\"Mira nuestras últimas novedades\",\"body\":\"<html><body><h1>¡Hola!</h1></body></html>\",\"body_plain\":\"string\",\"body_amp\":\"string\"}"


          headers = { ''content-type'': "application/json" }


          conn.request("POST", "/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language", payload, headers)


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"strings\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language\"\n\n\tpayload := strings.NewReader(\"{\\\"language\\\":\\\"es\\\",\\\"subject\\\":\\\"¡Hola, {{ customer.name }}!\\\",\\\"preheader_text\\\":\\\"Mira nuestras últimas novedades\\\",\\\"body\\\":\\\"<html><body><h1>¡Hola!</h1></body></html>\\\",\\\"body_plain\\\":\\\"string\\\",\\\"body_amp\\\":\\\"string\\\"}\")\n\n\treq, _ := http.NewRequest(\"POST\", url, payload)\n\n\treq.Header.Add(\"content-type\", \"application/json\")\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
  /v1/newsletters/{newsletter_id}/test_group/{test_group_id}/language/{language}:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: newsletter_id
      in: path
      required: true
      description: The identifier of a newsletter.
      schema:
        type: integer
    - name: test_group_id
      in: path
      description: The ID of the A/B test group.
      required: true
      schema:
        type: string
    - name: language
      in: path
      required: true
      description: A [language tag](/journeys/channels/subscriptions/unsubscribe-faqs/#currently-supported-languages) of a language variant. If you don't provide a language (an empty string), we'll use your default language. If the language variant does not exist, we'll return an error.
      schema:
        type: string
    get:
      summary: Get a translation in a newsletter test group
      operationId: getNewsletterVariantTranslationTest
      security:
      - Bearer-Auth: []
      description: Returns information about a specific language variant of a newsletter in an A/B test group. You can retrieve `test_group_ids` from [Get variants in a newsletter test group](/api/app/#operation/getNewsletterVariantTest).
      tags:
      - Newsletter Variants
      responses:
        '200':
          description: Returns newsletter `content` for a language variant in a test group.
          content:
            application/json:
              schema:
                type: object
                properties:
                  content:
                    x-scalar-ignore: true
                    allOf:
                    - x-scalar-ignore: true
                      type: object
                      properties:
                        id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of a newsletter variant—a language in a multi-language newsletter or a test in an A/B test.
                          readOnly: true
                        newsletter_id:
                          x-scalar-ignore: true
                          description: The identifier for a newsletter.
                          type: integer
                          example: 10
                        deduplicate_id:
                          x-scalar-ignore: true
                          type: string
                          readOnly: true
                          description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                          example: 15:1492548073
                        name:
                          type: string
                          description: The name of the variant, if it exists.
                          readOnly: true
                          example: newsletter variant A
                        layout:
                          type: string
                          description: The layout used for the variant, if it exists.
                          example: <html><body>{{ content }}</body></html>
                          readOnly: true
                        body:
                          type: string
                          description: The body of the variant. You cannot modify the body if you created it with our drag-and-drop editor.
                          example: <strong>Hello from the API</strong>
                        body_amp:
                          x-scalar-ignore: true
                          type: string
                          description: AMP-enabled content for your email. If a recipient's email client doesn't support AMP, they receive your `body` content instead. Make sure you're [set up to send AMP](/journeys/channels/email/layouts/amp-for-email/) first.
                        language:
                          x-scalar-ignore: true
                          type: string
                          description: The language variant for your message. If you don't use our [localization feature](/journeys/channels/localization/getting-started), or this is the default message, this value is an empty string.
                          example: fr
                          readOnly: true
                        type:
                          x-scalar-ignore: true
                          description: Channel type for a newsletter or newsletter content variant.
                          type: string
                          enum:
                          - email
                          - webhook
                          - twilio
                          - push
                          - in_app
                          - inbox
                          readOnly: true
                          example: email
                        from:
                          x-scalar-ignore: true
                          type: string
                          description: The address that the message is from, relevant if the action `type` is `email`.
                          readOnly: true
                          example: sentFrom@example.com
                        from_id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of the `from` address, commonly known as the "sender". Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 1
                        reply_to:
                          x-scalar-ignore: true
                          type: string
                          description: The address that receives replies for the message, if applicable.
                          readOnly: true
                          example: replyto@example.com
                        reply_to_id:
                          x-scalar-ignore: true
                          type:
                          - integer
                          - 'null'
                          description: The identifier for the `reply_to` address, if applicable. Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 38
                        preprocessor:
                          x-scalar-ignore: true
                          type: string
                          description: If CSS pre-processing is enabled, this key is populated with `premailer`. Note, Juice replaced Premailer as the pre-processor, but you will only see `premailer` as the value.
                          enum:
                          - premailer
                          readOnly: true
                        recipient:
                          x-scalar-ignore: true
                          description: The recipient address for an action.
                          type: string
                          example: '{{customer.email}}'
                        subject:
                          x-scalar-ignore: true
                          type: string
                          description: The subject line for an `email` action.
                          example: Did you get that thing I sent you?
                        cc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The carbon-copy address(es) for this action.
                          type: string
                        bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The blind-copy address(es) for this action.
                          type: string
                        fake_bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          type: boolean
                          description: 'If true, rather than sending true copies to BCC addresses, Customer.io sends a copy of the message with the subject line containing the recipient address(es).

                            '
                        preheader_text:
                          x-scalar-ignore: true
                          type: string
                          description: '[Also known as "preview text"](/journeys/channels/email/headers/custom-preheader-text/), this is the small block of text shown in an email inbox next to or underneath the subject line.

                            '
                    - type: object
                      properties:
                        headers:
                          x-scalar-ignore: true
                          description: A JSON string containing header objects with `name` and `value`. Names and values must be strings, with no non-ASCII characters or spaces. You can't overwrite reserved headers.
                          type: string
                          format: json
                          example: '[{"name":"X-Mailgun-Tag","value":"my-cool-tag"},{"name":"X-Custom-Header","value":"custom-value"}]'
        '400':
          description: The `language` does not exist.
        '404':
          description: The newsletter or variant does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request GET \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/test_group/{test_group_id}/language/{language}"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"GET\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Get.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("GET", "/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D\"\n\n\treq, _ := http.NewRequest(\"GET\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
    put:
      summary: Update a translation in a newsletter test group
      operationId: updateNewsletterTestTranslation
      security:
      - Bearer-Auth: []
      description: 'Update the translation of a newsletter variant in an A/B test. You can retrieve a list of `test_group_ids` from [Get variants in a newsletter test group](/api/app/#operation/getNewsletterVariantTest).


        **NOTE**: You cannot manage content made with Design Studio with this endpoint. Use the [Design Studio APIs](#tag/design-studio) instead.

        '
      tags:
      - Newsletter Variants
      requestBody:
        content:
          application/json:
            schema:
              oneOf:
              - $ref: '#/components/schemas/updateEmailContent'
              - $ref: '#/components/schemas/updateSmsContent'
              - $ref: '#/components/schemas/updatePushContent'
              - $ref: '#/components/schemas/updateWebhookContent'
              - $ref: '#/components/schemas/updateInboxContent'
              discriminator:
                propertyName: type
      responses:
        '200':
          description: Returns the updated newsletter variant.
          content:
            application/json:
              schema:
                type: object
                properties:
                  content:
                    x-scalar-ignore: true
                    allOf:
                    - x-scalar-ignore: true
                      type: object
                      properties:
                        id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of a newsletter variant—a language in a multi-language newsletter or a test in an A/B test.
                          readOnly: true
                        newsletter_id:
                          x-scalar-ignore: true
                          description: The identifier for a newsletter.
                          type: integer
                          example: 10
                        deduplicate_id:
                          x-scalar-ignore: true
                          type: string
                          readOnly: true
                          description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
                          example: 15:1492548073
                        name:
                          type: string
                          description: The name of the variant, if it exists.
                          readOnly: true
                          example: newsletter variant A
                        layout:
                          type: string
                          description: The layout used for the variant, if it exists.
                          example: <html><body>{{ content }}</body></html>
                          readOnly: true
                        body:
                          type: string
                          description: The body of the variant. You cannot modify the body if you created it with our drag-and-drop editor.
                          example: <strong>Hello from the API</strong>
                        body_amp:
                          x-scalar-ignore: true
                          type: string
                          description: AMP-enabled content for your email. If a recipient's email client doesn't support AMP, they receive your `body` content instead. Make sure you're [set up to send AMP](/journeys/channels/email/layouts/amp-for-email/) first.
                        language:
                          x-scalar-ignore: true
                          type: string
                          description: The language variant for your message. If you don't use our [localization feature](/journeys/channels/localization/getting-started), or this is the default message, this value is an empty string.
                          example: fr
                          readOnly: true
                        type:
                          x-scalar-ignore: true
                          description: Channel type for a newsletter or newsletter content variant.
                          type: string
                          enum:
                          - email
                          - webhook
                          - twilio
                          - push
                          - in_app
                          - inbox
                          readOnly: true
                          example: email
                        from:
                          x-scalar-ignore: true
                          type: string
                          description: The address that the message is from, relevant if the action `type` is `email`.
                          readOnly: true
                          example: sentFrom@example.com
                        from_id:
                          x-scalar-ignore: true
                          type: integer
                          description: The identifier of the `from` address, commonly known as the "sender". Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 1
                        reply_to:
                          x-scalar-ignore: true
                          type: string
                          description: The address that receives replies for the message, if applicable.
                          readOnly: true
                          example: replyto@example.com
                        reply_to_id:
                          x-scalar-ignore: true
                          type:
                          - integer
                          - 'null'
                          description: The identifier for the `reply_to` address, if applicable. Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                          example: 38
                        preprocessor:
                          x-scalar-ignore: true
                          type: string
                          description: If CSS pre-processing is enabled, this key is populated with `premailer`. Note, Juice replaced Premailer as the pre-processor, but you will only see `premailer` as the value.
                          enum:
                          - premailer
                          readOnly: true
                        recipient:
                          x-scalar-ignore: true
                          description: The recipient address for an action.
                          type: string
                          example: '{{customer.email}}'
                        subject:
                          x-scalar-ignore: true
                          type: string
                          description: The subject line for an `email` action.
                          example: Did you get that thing I sent you?
                        cc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The carbon-copy address(es) for this action.
                          type: string
                        bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          description: The blind-copy address(es) for this action.
                          type: string
                        fake_bcc:
                          x-scalar-ignore: true
                          readOnly: true
                          type: boolean
                          description: 'If true, rather than sending true copies to BCC addresses, Customer.io sends a copy of the message with the subject line containing the recipient address(es).

                            '
                        preheader_text:
                          x-scalar-ignore: true
                          type: string
                          description: '[Also known as "preview text"](/journeys/channels/email/headers/custom-preheader-text/), this is the small block of text shown in an email inbox next to or underneath the subject line.

                            '
                    - type: object
                      properties:
                        headers:
                          x-scalar-ignore: true
                          description: A JSON string containing header objects with `name` and `value`. Names and values must be strings, with no non-ASCII characters or spaces. You can't overwrite reserved headers.
                          type: string
                          format: json
                          example: '[{"name":"X-Mailgun-Tag","value":"my-cool-tag"},{"name":"X-Custom-Header","value":"custom-value"}]'
        '400':
          description: The `language` does not exist.
        '404':
          description: The newsletter or variant does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: json
        label: JSON
        source: '{}'
      - lang: Shell + Curl
        source: "curl --request PUT \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/test_group/{test_group_id}/language/{language} \\\n  --header 'content-type: application/json' \\\n  --data '{\"body\":\"string\",\"body_amp\":\"string\",\"body_plain\":\"string\",\"subject\":\"Did you get that thing I sent you?\",\"preheader_text\":\"string\",\"from_id\":1,\"reply_to_id\":38,\"recipient\":\"string\"}'"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"PUT\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D\",\n  \"headers\": {\n    \"content-type\": \"application/json\"\n  }\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.write(JSON.stringify({\n  body: 'string',\n  body_amp: 'string',\n  body_plain: 'string',\n  subject: 'Did you get that thing I sent you?',\n  preheader_text: 'string',\n  from_id: 1,\n  reply_to_id: 38,\n  recipient: 'string'\n}));\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Put.new(url)

          request["content-type"] = ''application/json''

          request.body = "{\"body\":\"string\",\"body_amp\":\"string\",\"body_plain\":\"string\",\"subject\":\"Did you get that thing I sent you?\",\"preheader_text\":\"string\",\"from_id\":1,\"reply_to_id\":38,\"recipient\":\"string\"}"


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          payload = "{\"body\":\"string\",\"body_amp\":\"string\",\"body_plain\":\"string\",\"subject\":\"Did you get that thing I sent you?\",\"preheader_text\":\"string\",\"from_id\":1,\"reply_to_id\":38,\"recipient\":\"string\"}"


          headers = { ''content-type'': "application/json" }


          conn.request("PUT", "/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D", payload, headers)


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"strings\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D\"\n\n\tpayload := strings.NewReader(\"{\\\"body\\\":\\\"string\\\",\\\"body_amp\\\":\\\"string\\\",\\\"body_plain\\\":\\\"string\\\",\\\"subject\\\":\\\"Did you get that thing I sent you?\\\",\\\"preheader_text\\\":\\\"string\\\",\\\"from_id\\\":1,\\\"reply_to_id\\\":38,\\\"recipient\\\":\\\"string\\\"}\")\n\n\treq, _ := http.NewRequest(\"PUT\", url, payload)\n\n\treq.Header.Add(\"content-type\", \"application/json\")\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
    delete:
      summary: Delete a translation in a newsletter test group
      operationId: deleteNewsletterTestLanguageVariant
      security:
      - Bearer-Auth: []
      description: 'Delete a specific language variant of a newsletter in an A/B test group. You cannot delete the default language variant. If your newsletter has already been sent, you cannot delete language variants.


        You can retrieve a list of `test_group_ids` from [List A/B test groups in a newsletter](#operation/getNewsletterTestGroups).

        '
      tags:
      - Newsletter Variants
      responses:
        '204':
          description: Success. No content.
        '400':
          description: You cannot delete the default language variant, or the newsletter has already been sent. It may also mean the `test_group_id` does not exist.
        '404':
          description: The newsletter or language variant does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request DELETE \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/newsletters/{newsletter_id}/test_group/{test_group_id}/language/{language}"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"DELETE\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Delete.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("DELETE", "/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/newsletters/%7Bnewsletter_id%7D/test_group/%7Btest_group_id%7D/language/%7Blanguage%7D\"\n\n\treq, _ := http.NewRequest(\"DELETE\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
components:
  schemas:
    updateEmailContent:
      title: Email
      description: 'Update the contents of an email newsletter variant. You can set the sender with `from_id`. If you don''t provide it, the existing sender is preserved.

        '
      allOf:
      - type: object
        properties:
          type:
            x-scalar-ignore: true
            description: Channel type for a newsletter or newsletter content variant.
            type: string
            enum:
            - email
            - webhook
            - twilio
            - push
            - in_app
            - inbox
            readOnly: true
            example: email
          deduplicate_id:
            x-scalar-ignore: true
            type: string
            readOnly: true
            description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
            example: 15:1492548073
      - type: object
        properties:
          type:
            type: string
            enum:
            - email
            readOnly: true
          body:
            type: string
            description: The HTML body of the email. You cannot modify the body if you created the newsletter with Design Studio or the drag-and-drop editor.
          body_amp:
            x-scalar-ignore: true
            type: string
            description: AMP-enabled content for your email. If a recipient's email client doesn't support AMP, they receive your `body` content instead. Make sure you're [set up to send AMP](/journeys/channels/email/layouts/amp-for-email/) first.
          body_plain:
            x-scalar-ignore: true
            type: string
            description: By default, your workspace generates a plaintext version of your message body for each delivery. Use this key to override the default plain text body.
          subject:
            x-scalar-ignore: true
            type: string
            description: The subject line for an `email` action.
            example: Did you get that thing I sent you?
          preheader_text:
            x-scalar-ignore: true
            type: string
            description: '[Also known as "preview text"](/journeys/channels/email/headers/custom-preheader-text/), this is the small block of text shown in an email inbox next to or underneath the subject line.

              '
          from_id:
            x-scalar-ignore: true
            type: integer
            description: The identifier of the `from` address, commonly known as the "sender". Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
            example: 1
          reply_to_id:
            x-scalar-ignore: true
            type:
            - integer
            - 'null'
            description: The identifier for the `reply_to` address, if applicable. Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
            example: 38
          recipient:
            type: string
            description: The recipient address for the newsletter. By default, it's `{{customer.email}}`.
    updateWebhookContent:
      title: Webhook
      description: Update the contents of a webhook newsletter variant.
      allOf:
      - type: object
        properties:
          type:
            x-scalar-ignore: true
            description: Channel type for a newsletter or newsletter content variant.
            type: string
            enum:
            - email
            - webhook
            - twilio
            - push
            - in_app
            - inbox
            readOnly: true
            example: email
          deduplicate_id:
            x-scalar-ignore: true
            type: string
            readOnly: true
            description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
            example: 15:1492548073
      - type: object
        properties:
          type:
            type: string
            enum:
            - webhook
            readOnly: true
          body:
            type: string
            description: The body content of the webhook request.
            example: '{"channel":"#marketing","text":"Newsletter sent to {{ customer.email }}"}'
          headers:
            x-scalar-ignore: true
            description: Headers you want to add or update. Names and values must be strings, with no non-ASCII characters or spaces. You can't overwrite reserved headers.
            type: array
            items:
              type: object
              properties:
                name:
                  type: string
                  description: The name of the header.
                value:
                  type: string
                  description: The value of the header.
              example:
              - name: X-Mailgun-Tag
                value: my-cool-tag
    updateInboxContent:
      title: Inbox message
      description: Update the contents of an inbox message newsletter variant.
      allOf:
      - type: object
        properties:
          type:
            x-scalar-ignore: true
            description: Channel type for a newsletter or newsletter content variant.
            type: string
            enum:
            - email
            - webhook
            - twilio
            - push
            - in_app
            - inbox
            readOnly: true
            example: email
          deduplicate_id:
            x-scalar-ignore: true
            type: string
            readOnly: true
            description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
            example: 15:1492548073
      - type: object
        properties:
          type:
            type: string
            enum:
            - inbox
            readOnly: true
          body_json:
            type: string
            description: 'JSON body content for the inbox message, as a stringified JSON object. The fields you include depend on how you [set up your inbox](/journeys/channels/in-app/inbox/setup/):

              - `topics`—array, topics your audience can filter by in their inbox

              - `type`—string, context that helps render the inbox message

              - `properties`—object, your message info like the title, body, link, and image

              - `expiration`—object; if omitted, the message expires after 30 days. Otherwise set `type` (`relative` or `absolute`), `unit` (`seconds`, `minutes`, `hours`, or `days`; relative only), and `value` (number of units, or a unix timestamp if absolute)

              '
            example: '{"topics": ["general", "updates"], "type": "notification", "expiration": {"type": "relative", "value": "30", "unit": "days"}, "properties": {"title": "Welcome!", "message": "Thanks for signing up", "link": "https://customer.io"}}'
    updateSmsContent:
      title: SMS
      description: Update the contents of an SMS newsletter variant.
      allOf:
      - type: object
        properties:
          type:
            x-scalar-ignore: true
            description: Channel type for a newsletter or newsletter content variant.
            type: string
            enum:
            - email
            - webhook
            - twilio
            - push
            - in_app
            - inbox
            readOnly: true
            example: email
          deduplicate_id:
            x-scalar-ignore: true
            type: string
            readOnly: true
            description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
            example: 15:1492548073
      - type: object
        properties:
          type:
            type: string
            enum:
            - twilio
            readOnly: true
          body:
            type: string
            description: The body of the SMS message.
            example: Hi {{ customer.first_name }}, check out our latest deals!
    updatePushContent:
      title: Push
      description: Update the contents of a push notification newsletter variant.
      allOf:
      - type: object
        properties:
          type:
            x-scalar-ignore: true
            description: Channel type for a newsletter or newsletter content variant.
            type: string
            enum:
            - email
            - webhook
            - twilio
            - push
            - in_app
            - inbox
            readOnly: true
            example: email
          deduplicate_id:
            x-scalar-ignore: true
            type: string
            readOnly: true
            description: An identifier in the format `id:timestamp` where the id is for the object you're working with (Campaigns, Deliveries, Exports, Identities, Newsletters, Segments, and Templates), and the timestamp is the last time the object was updated.
            example: 15:1492548073
      - type: object
        properties:
          type:
            type: string
            enum:
            - push
            readOnly: true
          subject:
            type: string
            description: The title of the push notification.
            example: 24-hour flash sale!
          body:
            type: string
            description: The body of the push notification.
            example: Get 30% off everything. Tap to shop now.
  securitySchemes:
    Bearer-Auth:
      type: http
      scheme: bearer
      description: 'The App API uses a bearer authentication scheme.


        You can generate a bearer token, known as an **App API Key**, with a defined scope in [your account settings](https://fly.customer.io/settings/api_credentials?keyType=app). [Learn more about bearer authorization in Customer.io](/accounts/settings/managing-credentials).

        '
    ServiceAccount-Auth:
      x-scalar-ignore: true
      type: http
      scheme: bearer
      bearerFormat: sa_live_
      description: 'Transactional send endpoints (`/v1/send/email`, `/v1/send/push`, `/v1/send/sms`, `/v1/send/in_app`, `/v1/send/inbox_message`) also accept a service-account bearer token, prefixed with `sa_live_`. Service-account tokens work across workspaces, so you must pass the target workspace as the `X-Workspace-Id` header on each request.


        Service-account tokens are intended for testing and one-off sends—for example, using the Customer.io CLI with an AI agent like Claude to verify that a transactional message renders correctly before wiring it into your production backend. **For the production integration that triggers the message from your application, use an App API Key instead**: it''s workspace-scoped, easier to rotate, and has a smaller blast radius.


        Service-account tokens are server-side credentials. Treat them like any API key—keep them in environment variables or a secret manager, and never embed them in client-side code, mobile apps, or other untrusted contexts.

        '
    bearerAuth:
      type: http
      scheme: bearer
      description: API key passed as a Bearer token