openapi: 3.2.0
info:
  version: 1.0.0
  title: Customer.io Journeys API Reference Email testing API
  description: Customer.io provides REST APIs to send real-time customer data, retrieve data from your account, and trigger messages.
servers:
- url: https://track.customer.io
  description: The base URL for the Track API. Track endpoints use basic authentication with your Site ID as the user name and your secret key as the password.
- url: https://track-eu.customer.io
  description: The base URL for the Track API (EU region). Track endpoints use basic authentication with your Site ID as the user name and your secret key as the password.
- 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: Email testing
  description: Check an email before you publish or send it.
paths:
  /v1/design_studio/emails/{id}/render:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    get:
      tags:
      - Email testing
      summary: Render an email
      description: 'Returns email-ready HTML. Use this endpoint to inspect your compiled markup.


        Liquid tags are left intact—`{{customer.first_name}}` stays in the output as written. To evaluate liquid against real profile data instead, use Preview an email.


        The render, preview, review, link, and publish endpoints share a rate limit of 5 requests per second per workspace.'
      operationId: renderEmail
      security:
      - Bearer-Auth: []
      parameters:
      - $ref: '#/components/parameters/email_variant_id'
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/EmailRenderResponse'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          description: "Possible reasons:\n  - The `design_studio_api_manage` feature isn't enabled for this workspace\n  - The email node doesn't exist\n"
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
  /v1/design_studio/emails/{id}/preview:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    post:
      tags:
      - Email testing
      summary: Preview an email
      description: 'Returns an email with liquid fully evaluated against data you provide. The response includes the final HTML as a recipient would see it, along with liquid errors.


        Omit the body or send `{}` to render your fallback values: a variable with a `default` filter renders its fallback, and each variable without one reports an error in the response''s `errors` object.


        The render, preview, review, link, and publish endpoints share a rate limit of 5 requests per second per workspace.'
      operationId: previewEmail
      security:
      - Bearer-Auth: []
      parameters:
      - $ref: '#/components/parameters/email_variant_id'
      requestBody:
        required: false
        description: All fields are optional.
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/EmailPreviewRequest'
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/EmailPreviewResponse'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          description: "Possible reasons:\n  - The `design_studio_api_manage` feature isn't enabled for this workspace\n  - The email node doesn't exist\n"
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
  /v1/design_studio/emails/{id}/test_send:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    post:
      tags:
      - Email testing
      summary: Send a test email
      description: 'Sends a test email to a real inbox through your sending domain using the content saved to Design Studio. The test includes the tracking pixel and link parameters a real send would add, so you can see your email as it would appear in an actual email client. To get the rendered HTML back in the API response instead, use Preview an email.


        * **If you already linked the email to a workflow**, then keep in mind that what''s *saved* to Design Studio may differ from what''s *published* to the linked workflow. Make sure you publish your changes when you''re ready to push them to your linked workflow.


        * **If your email has translations**, you have to send this request separately for each language variant. Pass the ID of the specific translation you want to test, which you can retrieve from List email translations.


        * **If the email contains liquid variables**, you can provide sample data in the request body to check how the liquid renders. Without sample data, the send still succeeds, but each variable renders as an empty string and the response includes a warning. A variable with a fallback filter like `default` renders its fallback instead. A liquid syntax error, like a missing close tag, always fails the request.


        Your account has a set number of test emails you can send per day. This endpoint counts towards that quota. Learn more in Plan features.'
      operationId: testSendEmail
      security:
      - Bearer-Auth: []
      parameters:
      - $ref: '#/components/parameters/email_variant_id'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/TestSendEmailRequest'
            example:
              to:
              - pigeon@customer.io
              - penguin@customer.io
              customer_id: '5'
              customer:
                first_name: Ada
                vip: gold
                cio_subscription_preferences: '{"topics":{"topic_2":true}}'
              prepend_test: true
      responses:
        '200':
          description: Test accepted for delivery
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TestSendEmailResponse'
        '400':
          description: The ID isn't a valid email node, your account isn't verified yet and `to` holds an address it can't send to, or you've reached your [daily test-send limit](/accounts/billing/plan-features/#general-features).
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          description: The email node doesn't exist.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
              example:
                errors:
                - detail: email not found
                  status: '404'
        '422':
          description: 'A request field is invalid or the email''s liquid didn''t render. Each error''s `source.pointer` names what failed, as `/data/attributes/<name>`. That name isn''t always something you sent: `node_id` points at the email itself, and a liquid error can name `url_params`, `layout`, or `snippets`.

            '
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
              example:
                errors:
                - detail: 'to is required: a test send made with an API key has no user to default the recipient to'
                  status: '422'
                  source:
                    pointer: /data/attributes/to
        '429':
          $ref: '#/components/responses/TestSendRateLimited'
  /v1/design_studio/emails/{id}/review:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    get:
      tags:
      - Email testing
      summary: Review an email
      description: 'Checks an email''s saved content for errors and suggests how to improve accessibility, styling, and more. This runs the same process as the *Review* panel in Design Studio and returns a readiness score, a status per check, and how to fix issues.


        This endpoint reviews **a single translation** based on the `:id` you pass. Call this endpoint for each language variant to review each translation.


        **Checks**

        - `liquid` — Liquid syntax: broken tags, invalid filters, unclosed blocks. Does not report missing variables; use the preview endpoint with sample data to validate variable resolution.

        - `failed-components` — Custom components that fail to compile. Always `skipped` on the API; it''s a browser-runtime-only signal.

        - `source` — Raw markup the editor stores, before liquid rendering. Checks for reserved internal HTML attributes, multiple root elements, and design-token clashes.

        - `links` — Broken URLs, validated over HTTP (capped at 100 links per review).

        - `images` — Broken image URLs and missing alt text (capped at 100 images per review).

        - `accessibility` — WCAG accessibility issues.

        - `spam` — SpamAssassin score.

        - `unsubscribe` — Presence of an unsubscribe link.

        - `implied-links` — Bare URLs or email addresses that should be wrapped in `` tags.

        - `html-clip` — Gmail''s 102 KB clipping threshold.

        - `preheader` — Preheader text presence and quality.


        The render, preview, review, link, and publish endpoints share a rate limit of 5 requests per second per workspace.'
      operationId: reviewEmail
      security:
      - Bearer-Auth: []
      parameters:
      - name: id
        in: path
        required: true
        description: 'The UUID of the email node. This can be the default-language node or a specific translation node.

          '
        schema:
          type: string
          format: uuid
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/EmailReviewResponse'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          description: "Possible reasons:\n  - The `design_studio_api_manage` feature isn't enabled for this workspace\n  - The email node doesn't exist\n"
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
  /v1/design_studio/inbox_previews/clients:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    get:
      tags:
      - Email testing
      summary: List inbox preview options
      description: 'Returns the catalog of email clients and devices available for inbox previews.


        Use the `id` values returned by this endpoint as `client_ids` when you send for an inbox preview.'
      operationId: listInboxPreviewClients
      security:
      - Bearer-Auth: []
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  clients:
                    type: array
                    items:
                      $ref: '#/components/schemas/InboxPreviewClient'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/InboxPreviewNotEnabled'
        '429':
          $ref: '#/components/responses/InboxPreviewReadRateLimited'
        '503':
          $ref: '#/components/responses/InboxPreviewCatalogUnavailable'
  /v1/design_studio/inbox_previews/credits:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    get:
      tags:
      - Email testing
      summary: Get preview credit balance
      description: 'Returns your account''s credit balance for inbox previews. Your credit balance determines how many previews you can generate in your account.


        Learn more about how inbox previews use credits.'
      operationId: getInboxPreviewCredits
      security:
      - Bearer-Auth: []
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  credits:
                    type: array
                    items:
                      $ref: '#/components/schemas/InboxPreviewCreditPool'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/InboxPreviewNotEnabled'
        '429':
          $ref: '#/components/responses/InboxPreviewReadRateLimited'
  /v1/design_studio/emails/{id}/inbox_previews:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    post:
      tags:
      - Email testing
      summary: Send for inbox previews
      description: 'Initiate one or more inbox previews for an email. This uses inbox preview credits; check your balance with Get preview credit balance. **Learn how billing for inbox previews work before you call this endpoint.**


        Use List emails to get your email''s ID. If the email has translations, call List email translations to get the ID of the language variant you want a preview of.


        You can retrieve client IDs from List inbox preview options.


        This call does not return the preview file. It returns a `run_id`; poll Get an inbox preview job with it, then fetch each tile''s capture URL from that response.


        Submitting the same email, content, and devices again on the same UTC day returns the existing run instead of starting a new one, with `replayed` set to `true` and no second charge. The same happens the next day if that run is still processing, or if a concurrent identical request gets there first. Resubmitting a stuck run is safe and free—it hands you the same run back rather than starting a second one.'
      operationId: submitInboxPreview
      security:
      - Bearer-Auth: []
      parameters:
      - $ref: '#/components/parameters/email_variant_id'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
              - client_ids
              properties:
                client_ids:
                  type: array
                  description: 'The identifiers of the preview options you want. You can retrieve client IDs from [List inbox preview options](/integrations/api/design-studio/tag/email-testing/listInboxPreviewClients/).

                    '
                  items:
                    type: string
                  minItems: 1
                  maxItems: 150
                sample_data:
                  type: object
                  description: 'Liquid variables to render with, as a JSON object—any shape is accepted, from flat variables like `{"first_name": "Janine"}` to nested ones like `{"customer": {"first_name": "Janine"}}`. Defaults to none, which fails the render on any variable the content needs beyond the ones a preview already sets for you. Set `lax_mode` to render missing variables as blank instead. Limited to 128 KB.

                    '
                  additionalProperties: true
                name:
                  type: string
                  description: A label for the batch of previews, shown in [preview history](/integrations/api/design-studio/tag/email-testing/listInboxPreviewJobs/).
                  maxLength: 191
                lax_mode:
                  type: boolean
                  description: Set to `true` to render liquid variables missing from `sample_data` as blank instead of failing the job.
                  default: false
              example:
                client_ids:
                - android12_gmailapp_pixel6_dm
                - android12_gmailapp_pixel6_dm_dark
                sample_data:
                  customer:
                    first_name: Janine
                name: Welcome email previews
      responses:
        '200':
          description: Preview job submitted
          content:
            application/json:
              schema:
                type: object
                properties:
                  run_id:
                    type: integer
                    description: ID of the preview job. Check when it's complete with [Get an inbox preview job](/integrations/api/design-studio/tag/email-testing/getInboxPreviewJob/).
                  replayed:
                    type: boolean
                    description: '`true` when this call returned an existing run instead of starting a new one, and you weren''t charged a second time for it. This happens for an identical request (same email, content, and devices) submitted again on the same UTC day, an identical request from the day before that''s still processing, or a concurrent identical request that got there first. The run may belong to another client in your workspace, including the Journeys UI—`created_at` is that run''s, and a `name` you send is applied to it.

                      '
              example:
                run_id: 10
                replayed: false
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '403':
          $ref: '#/components/responses/InboxPreviewNotChargeable'
        '404':
          $ref: '#/components/responses/NotFound'
        '409':
          $ref: '#/components/responses/InboxPreviewSubmitConflict'
        '422':
          $ref: '#/components/responses/InboxPreviewInsufficientCredits'
        '429':
          $ref: '#/components/responses/InboxPreviewRateLimited'
        '503':
          $ref: '#/components/responses/InboxPreviewRenderUnavailable'
  /v1/design_studio/emails/{id}/inbox_previews/{run_id}:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    get:
      tags:
      - Email testing
      summary: Get an inbox preview job
      description: Returns the status of a preview job submitted with Send for inbox previews, including each preview's settings.
      operationId: getInboxPreviewJob
      security:
      - Bearer-Auth: []
      parameters:
      - $ref: '#/components/parameters/email_variant_id'
      - $ref: '#/components/parameters/run_id'
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/InboxPreviewJob'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          description: The job doesn't exist, or inbox previews aren't enabled for your workspace.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '429':
          $ref: '#/components/responses/InboxPreviewReadRateLimited'
  /v1/design_studio/emails/{id}/inbox_previews/{run_id}/captures/{client_id}:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    get:
      tags:
      - Email testing
      summary: Get a preview screenshot
      description: Returns the image bytes for a single preview job, proxied from the vendor. The response's content type matches whatever the vendor sent for that capture, which isn't always PNG, and the `Content-Disposition` filename's extension matches it. You can also use the URL paths in the response of Get an inbox preview job to complete this request.
      operationId: getInboxPreviewCapture
      security:
      - Bearer-Auth: []
      parameters:
      - $ref: '#/components/parameters/email_variant_id'
      - $ref: '#/components/parameters/run_id'
      - $ref: '#/components/parameters/preview_client_id'
      - name: variant
        in: query
        description: The image to return.
        schema:
          type: string
          enum:
          - screenshot
          - thumbnail
          - full_thumbnail
          default: screenshot
      - name: key
        in: query
        description: 'Only applies when `variant` is `screenshot`. Match this to a key in that tile''s `screenshots` object from [Get an inbox preview job](/integrations/api/design-studio/tag/email-testing/getInboxPreviewJob/)—most devices only have `default`, but some carry extra vendor-defined captures, like an image-blocking render.

          '
        schema:
          type: string
          default: default
      responses:
        '200':
          description: Image bytes for the requested capture, in whatever format the vendor sent it.
          content:
            image/png:
              schema:
                type: string
                format: binary
            image/jpeg:
              schema:
                type: string
                format: binary
            image/gif:
              schema:
                type: string
                format: binary
            image/webp:
              schema:
                type: string
                format: binary
            image/svg+xml:
              schema:
                type: string
                format: binary
            image/avif:
              schema:
                type: string
                format: binary
            image/bmp:
              schema:
                type: string
                format: binary
            image/tiff:
              schema:
                type: string
                format: binary
            image/x-icon:
              schema:
                type: string
                format: binary
        '400':
          description: Invalid `variant` value.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          description: The capture doesn't exist, is still rendering, bounced, or has expired, or inbox previews aren't enabled for your workspace.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '429':
          $ref: '#/components/responses/InboxPreviewReadRateLimited'
  /v1/design_studio/inbox_previews/jobs:
    servers:
    - url: https://api.customer.io
      description: The base URL for the Design Studio API. These endpoints use bearer authorization, and require an [App API Key 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 the Design Studio API (EU region). These endpoints use bearer authorization, and require an [App API Key that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    get:
      tags:
      - Email testing
      summary: List inbox preview history
      description: Returns a paginated history of inbox preview jobs across your workspace, or for a single email when you pass `node_id`. Only lists runs recent enough for their screenshots to still be viewable—an older run won't appear here even though it still exists.
      operationId: listInboxPreviewJobs
      security:
      - Bearer-Auth: []
      parameters:
      - name: node_id
        in: query
        description: Filter to preview jobs submitted for a specific email.
        schema:
          type: string
          format: uuid
      - name: limit
        in: query
        description: Number of jobs to return per page.
        schema:
          type: integer
          minimum: 1
          maximum: 200
          default: 50
      - name: cursor
        in: query
        description: A pagination cursor returned in the previous page's `meta.pagination.next_cursor`. Omit to return the first page.
        schema:
          type: string
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  preview_jobs:
                    type: array
                    items:
                      $ref: '#/components/schemas/InboxPreviewJobSummary'
                  meta:
                    $ref: '#/components/schemas/InboxPreviewJobsMeta'
              example:
                preview_jobs:
                - run_id: 2
                  node_id: 018fbb92-6d1e-7c33-9c2c-df6a2b5aa931
                  name: Welcome email previews
                  node_count: 1
                  is_processed: true
                  total_previews_requested: 12
                  total_previews_cached: 4
                  total_previews_succeeded: 8
                  total_previews_bounced: 0
                  total_previews_ready: 12
                  created_at: 1773856017
                  updated_at: 1773856032
                - run_id: 1
                  node_id: 018fbb90-1a2f-7e21-8f3d-56b1c0a2e410
                  name: Order confirmation previews
                  node_count: 1
                  is_processed: false
                  total_previews_requested: 10
                  total_previews_cached: 2
                  total_previews_succeeded: 0
                  total_previews_bounced: 0
                  total_previews_ready: 2
                  created_at: 1773855001
                  updated_at: 1773855950
                meta:
                  pagination:
                    limit: 50
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          description: Inbox previews aren't enabled for your workspace.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '429':
          $ref: '#/components/responses/InboxPreviewReadRateLimited'
components:
  parameters:
    run_id:
      name: run_id
      in: path
      required: true
      description: The ID of the inbox preview job, returned by [Send for inbox previews](/integrations/api/design-studio/tag/email-testing/submitInboxPreview/).
      schema:
        type: integer
    email_variant_id:
      name: id
      in: path
      required: true
      description: 'The UUID of the email. If your email has translations, this is the ID of a specific language variant.

        '
      schema:
        type: string
        format: uuid
    preview_client_id:
      name: client_id
      in: path
      required: true
      description: The device identifier for the capture, matching a value from `client_ids` in the response of [Send for inbox previews](/integrations/api/design-studio/tag/email-testing/submitInboxPreview/).
      schema:
        type: string
  schemas:
    TestSendEmailRequest:
      type: object
      required:
      - to
      properties:
        to:
          type: array
          items:
            type: string
          description: 'The email addresses you want to send the test to. You can send to up to 25 addresses per request; up to three addresses on a trial account; or a single address (the account owner''s address or your workspace''s delivery address) if your account isn''t verified yet.

            '
        customer_id:
          type:
          - string
          - 'null'
          description: 'The person whose profile attributes fill in `customer.*` liquid variables. Pass the person''s `cio_id` or the `id` that identifies them in your workspace. If nobody matches, the request fails. When you omit this field and don''t pass `customer` values, the email renders with empty `customer.*` values and the response includes a warning.

            '
        customer:
          type:
          - object
          - 'null'
          description: 'Sample profile attributes for `customer.*` liquid variables, as a flat object of values. Encode a nested value as a JSON string. You can pass this alongside `customer_id`: Customer.io uses the profile''s attributes, and a value here overrides the profile''s value for the same key.

            '
          additionalProperties: true
        event:
          type:
          - object
          - 'null'
          description: 'Sample event data for `event.*` liquid variables. The `event` key references trigger data for event-triggered automations.

            '
          additionalProperties: true
        trigger:
          type:
          - object
          - 'null'
          description: 'Sample trigger data for `trigger.*` liquid variables. The `trigger` key references trigger data for these specific workflows: API-triggered broadcasts or transactional messages.

            '
          additionalProperties: true
        lax:
          type: boolean
          default: false
          description: 'Set to `true` to render a liquid variable your sample data doesn''t cover as an empty string rather than failing the request. Only applies when you pass `customer_id` or `customer`; without sample data, the email renders this way anyway and the response includes a warning.

            '
        prepend_test:
          type: boolean
          default: false
          description: Set to `true` to add `[TEST]` to the start of the subject line.
        tracked:
          type: boolean
          description: 'Set to `true` to add a tracking pixel or `false` to leave it out. If you don''t pass this field, Customer.io uses the tracking setting of the workflow message the email is linked to, and adds the pixel when the email isn''t linked to a workflow message. Customer.io never adds the pixel for unverified accounts.

            '
    EmailReviewCheckStatus:
      type: object
      properties:
        status:
          type: string
          enum:
          - complete
          - degraded
          - error
          - skipped
          description: '`complete`: findings are authoritative. `degraded`: the check ran on reduced input (for example, some URL validations failed) — its findings aren''t authoritative. `error`: the check couldn''t run and contributed no findings. `skipped`: the check has no server-side signal for API callers.

            '
        error:
          type: string
          description: Present when `status` is `degraded` or `error`. Explains what was missing or what failed.
    EmailPreviewRequest:
      type: object
      properties:
        customer:
          type: object
          description: Customer profile attributes for `{{customer.*}}` variables.
        event:
          type: object
          description: Event attributes for `{{event.*}}`.
        trigger:
          type: object
          description: Trigger data for `{{trigger.*}}`.
        campaign:
          type: object
          description: Campaign metadata for `{{campaign.*}}`.
        message:
          type: object
          description: Message metadata for `{{message.*}}`.
        journey:
          type: object
          description: Journey metadata for `{{journey.*}}`.
        objects:
          type: object
          description: Related objects for `{{objects.*}}`.
        lax:
          type: boolean
          default: false
          description: 'Set to `true` if you want undefined variables to resolve to an empty string instead of reporting an error; this can help you focus on more important errors when you don''t provide sample data or fallback values. Liquid *syntax* errors (like broken tags and invalid filters) are always reported as errors.

            '
      example:
        customer:
          first_name: Jane
          email: jane@example.com
          plan: enterprise
        event:
          name: order_completed
          total: 149.99
    InboxPreviewCreditPool:
      type: object
      description: Credits available for generating inbox previews.
      properties:
        tier:
          type: string
          enum:
          - free
          - paid
          description: The credit tier this pool belongs to. The [`free` tier](/accounts/billing/inbox-previews/) covers two kinds of pools, the monthly allowance of 25 credits every account gets and any free pools Customer.io support has granted. Because of that, `free` can appear more than once in the response. The `paid` tier covers credits purchased for the account.
        credits_original:
          type: integer
          description: Credits originally granted for a tier.
        credits_remaining:
          type: integer
          description: Credits left to spend from this tier.
        expires_at:
          type:
          - integer
          - 'null'
          format: Unix timestamp
          description: When this pool's credits expire, if ever. Expiry is set per pool, not per tier—a purchased pool typically doesn't expire, but a free pool support granted can carry an expiration date. The monthly allowance's `expires_at` also reads `null` when Customer.io can't resolve your current billing period; that's a transient read issue, not a sign the allowance never expires.
      example:
      - tier: free
        credits_original: 25
        credits_remaining: 0
        expires_at: 1715769600
      - tier: paid
        credits_original: 100
        credits_remaining: 90
        expires_at: null
    EmailRenderResponse:
      type: object
      properties:
        node_id:
          type: string
          format: uuid
          description: The UUID of the rendered email node.
        node_type:
          type: string
          enum:
          - EMAIL
          description: Always `"EMAIL"`.
        html:
          type: string
          description: Full HTML with liquid tags left intact.
        text:
          type: string
          description: Plain text version of the email. Omitted unless you added a plain text version when you [created the email](/integrations/api/design-studio/tag/emails/createEmail/).
        language:
          type: string
          description: Language code if the node is a translation (for example, `"es"`). Omitted for default-language nodes.
        amp:
          type: string
          description: AMP HTML variant. Omitted unless you added an AMP version when you [created the email](/integrations/api/design-studio/tag/emails/createEmail/).
      example:
        node_id: 1a0cbb4e-09d3-402e-949e-f6732f021650
        node_type: EMAIL
        html: '<!doctype html>

          <html lang="und">...

          <p>{{customer.first_name}}, welcome!</p>

          ...

          </html>'
        text: <html><head></head><body style="margin:0"><div style="font-size:16px;line-height:1.5;font-family:Arial,Helvetica,sans-serif;white-space:pre-wrap;padding:10px;">{{customer.first_name}}, welcome!</div></body></html>
    InboxPreviewTile:
      type: object
      description: The data for a single preview.
      properties:
        client_id:
          type: string
          description: The preview identifier, matching a value from `client_ids` in the submit request.
        display_name:
          type: string
          description: Human-readable name of the client and device used to render the preview.
        os:
          type: string
          description: Operating system the client runs on.
        category:
          type: string
          enum:
          - Mobile
          - Application
          - Web
          description: Client category. `Mobile` is a phone's native mail app, for example the Gmail App on Android devices. `Application` is a desktop native mail app, for example Apple Mail on macOS. `Web` is webmail viewed in a desktop browser, for example Gmail.com in Firefox, and includes a `browser` value.
        browser:
          type: string
          description: Browser used to render the client, when applicable. Populates when `category` is `Web`.
        status:
          type: string
          enum:
          - Pending
          - Processing
          - Complete
          - Bounced
          description: The vendor's own status for this device's render. Only `Complete` and `Bounced` are terminal.
        screenshots:
          type: object
          description: Capture URLs keyed by image name—the full-size screenshot under `default`, plus a key per extra image the device renders. This is the only place the full-size URL appears; `thumbnail` and `full_thumbnail` are reduced variants. Omitted unless the render completed.
          additionalProperties:
            type: string
        thumbnail:
          type: string
          description: Capture URL for a reduced-size version of the default screenshot. Useful for grid/list views where you don't want to load full-size screenshots. Omitted unless the render completed.
        full_thumbnail:
          type: string
          description: Capture URL for a reduced, full-length version of the default screenshot. Omitted unless the render completed.
        cached:
          type: boolean
          description: Set when the item wasn't newly generated in this preview job because it had already been generated. Omitted when `false`.
        error:
          $ref: '#/components/schemas/InboxPreviewError'
          description: Present on every `Bounced` tile. Absent otherwise.
    InboxPreviewClient:
      type: object
      description: An email client available for inbox previews.
      properties:
        id:
          type: string
          description: Identifier to pass in `client_ids` when you send for an inbox preview.
          example: android12_gmailapp_pixel6_dm
        client:
          type: string
          description: Name of the email client and device.
          example: Gmail App Pixel 6
        os:
          type: string
          description: 'Operating system the client runs on. Look for `(Dark Mode)` if you want to locate preview options for dark mode.

            '
          example: Android 12 (Dark Mode)
        category:
          type: string
          enum:
          - Mobile
          - Application
          - Web
          description: 'Where the client renders. `Mobile` is a phone''s native mail app, for example the Gmail App on Android devices. `Application` is a desktop native mail app, for example Apple Mail on macOS. `Web` is webmail viewed in a desktop browser, for example Gmail.com in Firefox, and includes a `browser` value.

            '
          example: Mobile
        browser:
          type: string
          description: Browser used to render the client. Populates when `category` is `Web`.
          example: ''
    EmailPreviewHeaderError:
      type: object
      properties:
        name:
          type: array
          items:
            type: string
          description: Errors in the header name.
        value:
          type: array
          items:
            type: string
          description: Errors in the header value.
    EmailPreviewResponse:
      type: object
      properties:
        node_id:
          type: string
          format: uuid
          description: The UUID of the previewed email node.
        node_type:
          type: string
          enum:
          - EMAIL
          description: Always `"EMAIL"`.
        language:
          type: string
          description: Language code if the node is a translation. Omitted for default-language nodes.
        subject:
          type: string
          description: Evaluated subject line.
        html:
          type: string
          description: Final HTML with Liquid evaluated, the preheader injected, and dangerous tags removed.
        amp:
          type: string
          description: AMP HTML variant with liquid evaluated. Omitted if the email doesn't have an AMP version.
        text:
          type: string
          description: Plain-text body with liquid evaluated. Omitted if the email doesn't have a plain text version.
        plaintext_body:
          type: string
          description: The plain-text part a recipient would get—your plain text version with HTML tags stripped, or text generated from the final HTML if the email doesn't have one. Omitted when empty.
        from:
          type: string
          description: Resolved from address, for example `"Name <email>"`. Omitted when the email doesn't include a from address.
        preheader_text:
          type: string
          description: Evaluated preheader text. Omitted when the email doesn't include preheaders.
        errors:
          $ref: '#/components/schemas/EmailPreviewErrors'
        headers:
          type: array
          items:
            $ref: '#/components/schemas/EmailPreviewHeaderError'
          description: One entry per custom header that has Liquid errors. Omitted when there are none.
        links:
          type: array
          items:
            $ref: '#/components/schemas/EmailPreviewLink'
          description: Every link in the evaluated HTML body, with any per-link problems.
      example:
        node_id: 1a0cbb4e-09d3-402e-949e-f6732f021650
        node_type: EMAIL
        subject: Order Confirmation
        html: <!DOCTYPE html>...<p>Purchase info</p>...
        text: <html><head></head><body style="margin:0"><div style="font-size:16px;line-height:1.5;font-family:Arial,Helvetica,sans-serif;white-space:pre-wrap;padding:10px;">Thanks for your recent purchase!</div></body></html>
        plaintext_body: Thanks for your recent purchase!
        from: '"No reply" <noreply@example.com>'
        errors:
          subject: []
          body: []
          body_amp: []
          body_plain: []
          from: []
          reply_to: []
          bcc: []
          cc: []
          to: []
          preheader_text: []
          layout: []
          message: []
          snippets: []
          event: []
          trigger: []
        links:
        - url: https://example.com/orders
          text: View your order
          tracked: true
          errors: []
    EmailReviewFinding:
      type: object
      properties:
        id:
          type: string
          description: Identifier for this finding, unique within the response.
        check:
          type: string
          description: Which check produced this finding.
        severity:
          type: string
          enum:
          - error
          - warning
          - tip
          description: Fix all errors to make sure your recipients get your email and you follow compliance requirements. Review warnings and tips to improve the quality of your email.
        state:
          type: string
          enum:
          - pass
          - fail
          description: Whether this finding represents an issue. Passing findings don't affect the score.
        title:
          type: string
          description: Short human-readable title.
        summary:
          type: string
          description: Location context, for example "In the email body". Omitted when there's no additional context.
        details:
          type: string
          description: Explanation and suggested fix. Omitted when there's nothing more to add beyond the title.
    Error:
      type: object
      description: An error response containing one or more error details.
      properties:
        errors:
          type: array
          description: A list of errors that occurred while processing the request.
          items:
            type: object
            properties:
              detail:
                type: string
                description: A human-readable description of the error.
              status:
                type: string
                description: The HTTP status code for this error, as a string.
              source:
                type: object
                description: The request field that caused the error. Validation errors (`422`) include it.
                properties:
                  pointer:
                    type: string
                    description: The path to the field that failed, like `/data/attributes/content`.
              meta:
                type: object
                description: Additional detail about the error, when there is any. A failed publish uses this to list Liquid errors per language.
    EmailPreviewLink:
      type: object
      properties:
        url:
          type: string
          description: The link URL after liquid evaluation.
        text:
          type: string
          description: The link's visible text.
        tracked:
          type: boolean
          description: Whether Customer.io rewrites this link for click tracking when you send the email.
        errors:
          type: array
          items:
            type: string
          description: Problems with this link, like a relative URL or liquid tags that were URL-encoded. Empty when the link is fine.
    TestSendEmailResponse:
      type: object
      properties:
        node_id:
          type: string
          format: uuid
          description: The email node that was tested.
        node_type:
          type: string
          enum:
          - EMAIL
          description: The response represents an email.
        language:
          type: string
          description: The language code if the message is a language variant. Omitted for the default-language node.
        accepted:
          type: boolean
          description: Always `true` in a 200 response. Anything that stops the send returns a 4xx instead. Acceptance isn't proof of delivery.
        to:
          type: array
          items:
            type: string
          description: The recipients the test was sent to.
        subject:
          type: string
          description: The rendered subject line, including the `[TEST]` prefix if you set `prepend_test`.
        from:
          type: string
          description: 'The rendered `From` header the test was sent with.

            '
        warnings:
          type: array
          items:
            type: string
          description: 'The ways this test differs from a real send. Customer.io delivered the email anyway, so read these before you trust what landed in the inbox. You might see that no profile data was available, that context a test send can''t supply rendered as empty strings (like `campaign.*` or `message.*` on an email that isn''t linked to a workflow), that Customer.io ignored a routing key like `recipient` or `from_address` in your `event` or `trigger` data, or that a recipient field in the template failed to render. That last one doesn''t change who got the test: it goes only to the addresses in `to`. Omitted when there''s nothing to report.

            '
      example:
        node_id: 1a0cbb4e-09d3-402e-949e-f6732f021650
        node_type: EMAIL
        accepted: true
        to:
        - pigeon@customer.io
        - penguin@customer.io
        subject: '[TEST] Welcome Ada'
        from: '"No reply" <noreply@customer.io>'
    InboxPreviewJobsMeta:
      type: object
      properties:
        pagination:
          type: object
          properties:
            limit:
              type: integer
              description: The `limit` used for this page.
            next_cursor:
              type: string
              description: Pass this as `cursor` to fetch the next page. Omitted when there are no more results.
    InboxPreviewJob:
      type: object
      description: The status and results of an Inbox Previews job.
      properties:
        run_id:
          type: integer
          description: ID of the preview job.
        name:
          type: string
          description: The batch label provided when you sent an email for previews. Empty if none was given.
        client_ids:
          type: array
          description: The device identifiers requested for this job.
          items:
            type: string
        created_at:
          type: integer
          format: Unix timestamp
          description: When you submitted the preview job.
        updated_at:
          type: integer
          format: Unix timestamp
          description: When the job's status was last updated.
        is_processed:
          type: boolean
          description: '`true` once every device has settled, for the email in the path—a multi-language run reports each of its emails separately, so this doesn''t reflect the whole run when it covers more than one. Poll this field, and see the endpoint description for how often, and for when to give up.

            '
        total_previews_requested:
          type: integer
          description: Previews requested in the job, for the email in the path. On a settled run, this is normally `total_previews_cached` + `total_previews_succeeded` + `total_previews_bounced`.
        total_previews_cached:
          type: integer
          description: Previews served from an earlier run's screenshot. Not charged, and not counted in `total_previews_succeeded`.
        total_previews_succeeded:
          type: integer
          description: Previews this run generated itself, excluding cached ones. A fully cached run reports `0` here even though every tile is `Complete`—compare `total_previews_ready` against `total_previews_requested` instead to track progress.
        total_previews_bounced:
          type: integer
          description: Previews that produced no screenshot, whether the vendor bounced them or they failed on Customer.io's side. Their credits are refunded when the run settles.
        total_previews_ready:
          type: integer
          description: 'How many previews show a screenshot you can fetch, counted from the tiles themselves. This is the progress count to compare against `total_previews_requested`—`total_previews_succeeded` alone reads `0` on a fully cached run. It isn''t the completion signal; `is_processed` is. Because a tile can be served by an earlier screenshot of the same content while this run''s own render is still in flight, this can reach `total_previews_requested` before the run finishes.

            '
        previews:
          type: array
          description: One object per requested preview.
          items:
            $ref: '#/components/schemas/InboxPreviewTile'
    EmailPreviewErrors:
      type: object
      description: Per-field Liquid error arrays. All 15 fields are always present; an empty array means no errors for that field.
      properties:
        subject:
          type: array
          items:
            type: string
          description: Subject line Liquid errors.
        body:
          type: array
          items:
            type: string
          description: HTML body Liquid errors.
        body_amp:
          type: array
          items:
            type: string
          description: AMP body Liquid errors.
        body_plain:
          type: array
          items:
            type: string
          description: Plain-text body Liquid errors.
        from:
          type: array
          items:
            type: string
          description: From address Liquid errors.
        reply_to:
          type: array
          items:
            type: string
          description: Reply-to address Liquid errors.
        bcc:
          type: array
          items:
            type: string
          description: BCC field Liquid errors.
        cc:
          type: array
          items:
            type: string
          description: CC field Liquid errors.
        to:
          type: array
          items:
            type: string
          description: 'Recipient field Liquid errors, for example `"undefined variable: customer.email"`.

            '
        preheader_text:
          type: array
          items:
            type: string
          description: Preheader Liquid errors.
        layout:
          type: array
          items:
            type: string
          description: Layout template errors.
        message:
          type: array
          items:
            type: string
          description: Message-level errors.
        snippets:
          type: array
          items:
            type: string
          description: Snippet rendering errors.
        event:
          type: array
          items:
            type: string
          description: Event data Liquid errors.
        trigger:
          type: array
          items:
            type: string
          description: Trigger data Liquid errors.
    InboxPreviewJobSummary:
      type: object
      description: A summary entry in the inbox previews job history.
      properties:
        run_id:
          type: integer
          description: ID of the preview job.
        node_id:
          type: string
          format: uuid
          description: The email node the run covers, or the first of them when it covers several. Under a `node_id` filter, this is the matched node.
        name:
          type: string
          description: The batch label provided when the job was submitted.
        node_count:
          type: integer
          description: How many email nodes the run covers—more than one for a multi-language run. Under a `node_id` filter, how many of them matched.
        is_processed:
          type: boolean
          description: '`true` once every device of every counted node has settled. Under a `node_id` filter, "counted" means the matched nodes only.

            '
        total_previews_requested:
          type: integer
          description: Previews requested across the counted nodes. On a settled run, this is normally `total_previews_cached` + `total_previews_succeeded` + `total_previews_bounced`.
        total_previews_cached:
          type: integer
          description: Previews served from an earlier run's screenshot. Not charged, and not counted in `total_previews_succeeded`.
        total_previews_succeeded:
          type: integer
          description: Previews this run generated itself, as stored when each node settled. Excludes cached ones, and counts only nodes that have settled—so a run still generating reads `0` here even once some devices are done.
        total_previews_bounced:
          type: integer
          description: Previews that produced no screenshot, whether the vendor bounced them or they failed on Customer.io's side, as stored when each node settled. Their credits are refunded.
        total_previews_ready:
          type: integer
          description: '`total_previews_cached` + `total_previews_succeeded`, from the counters stored on the run. The cached half is final as soon as the run exists; the succeeded half counts only nodes that have settled, so a run still generating reads low until `is_processed` is `true`. This list can''t see a tile served by an earlier screenshot of the same content, so it can read lower than [Get an inbox preview job](/integrations/api/design-studio/tag/email-testing/getInboxPreviewJob/) reports for the same run—poll the run for the authoritative count.

            '
        created_at:
          type: integer
          format: Unix timestamp
          description: When the job was submitted.
        updated_at:
          type: integer
          format: Unix timestamp
          description: When the job's status was last updated.
    InboxPreviewError:
      type: object
      description: Details for a tile whose rendering failed.
      properties:
        type:
          type: string
          enum:
          - bounced
          - vendor_timeout
          - client_rejected
          - vendor_request
          - abandoned
          - expired
          - other
          description: "Why this device has no screenshot:\n  - `bounced`: the vendor rendered the device and reported a bounce.\n  - `vendor_timeout`: submitted to the vendor, but didn't finish in time.\n  - `client_rejected`: the vendor refused the device id.\n  - `vendor_request`: the submission to the vendor itself failed.\n  - `abandoned`: submitted, but the outcome is unknown.\n  - `expired`: the screenshot rendered successfully but has since aged out of its retention window and is no longer available. Unlike the other types, this isn't a render failure.\n  - `other`: any other cause.\n\nA tile with any of these types (except `expired`) was refunded its credit.\n"
        message:
          type: string
          description: A human-readable explanation, safe to show to a user.
    EmailReviewScore:
      type: object
      description: Readiness score. Omitted when `status` is `render_failed`.
      properties:
        score:
          type: integer
          description: '0–100 readiness estimate. Starts at 100 and is reduced per failing finding. An error drops the score to 60 or below; fix all errors to make sure your recipients get your email and you follow compliance requirements. See **findings** to locate errors.

            '
        counts:
          type: object
          description: Finding counts by severity across all checks.
          properties:
            error:
              type: integer
              description: The number of failing `error` findings.
            warning:
              type: integer
              description: The number of failing `warning` findings.
            tip:
              type: integer
              description: The number of failing `tip` findings.
    EmailReviewResponse:
      type: object
      properties:
        node_id:
          type: string
          format: uuid
          description: The UUID of the reviewed email node.
        status:
          type: string
          enum:
          - complete
          - partial
          - render_failed
          description: "- `complete`: every check ran to completion. \n- `partial`: at least one check errored, ran on reduced input, or was skipped. `failed-components` is always skipped and doesn't [affect this status. If you get a `partial` status, send the request again after a few seconds to try to get a complete set of findings.\n- `render_failed`: the underlying render failed; no checks ran, `score` is omitted, and `findings` is empty. If it's a timeout, send the request again after a few seconds. If it's a content or compilation error, fix the email before sending the request again.\n"
        score:
          $ref: '#/components/schemas/EmailReviewScore'
        checks:
          type: object
          description: Per-check status, keyed by check name. See the endpoint description for the full list of checks.
          additionalProperties:
            $ref: '#/components/schemas/EmailReviewCheckStatus'
        findings:
          type: array
          items:
            $ref: '#/components/schemas/EmailReviewFinding'
      example:
        node_id: 887d804e-9199-4a65-ae26-315e825344bc
        status: complete
        score:
          score: 86
          counts:
            error: 0
            warning: 1
            tip: 1
        checks:
          liquid:
            status: complete
          failed-components:
            status: skipped
          source:
            status: complete
          links:
            status: complete
          images:
            status: complete
          accessibility:
            status: complete
          spam:
            status: complete
          unsubscribe:
            status: complete
          implied-links:
            status: complete
          html-clip:
            status: complete
          preheader:
            status: complete
        findings:
        - id: unsubscribe
          check: unsubscribe
          severity: warning
          state: fail
          title: No unsubscribe link
          details: Add {% unsubscribe %} or use {% unsubscribe_url %} as the href.
        - id: preheader
          check: preheader
          severity: tip
          state: fail
          title: No preheader text
          details: Add a short preheader to improve open rates.
  responses:
    InboxPreviewSubmitConflict:
      description: "A retry crossed an interrupted charge for this batch. This means one of two things:\n  - The batch was already charged and settled today.\n  - An earlier attempt at the same batch is still being reconciled.\n\nChange the devices or nodes you're previewing, or retry later. Either way, you weren't double-charged.\n"
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: this preview batch was already charged and settled today. Change the devices or nodes you are previewing, or try again tomorrow.
              status: '409'
    BadRequest:
      description: The request is invalid due to malformed parameters, missing required fields, or constraint violations.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    InboxPreviewNotChargeable:
      description: Your account can't be charged for inbox preview credits right now. Credits are account-level—every workspace on the account draws from the same pools, so this isn't specific to the workspace in your credentials.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: this account cannot be charged for inbox previews
              status: '403'
    InboxPreviewInsufficientCredits:
      description: Not enough inbox preview credits to cover every device in `client_ids`. The message names both figures, so you can size a top-up without a separate call to [Get preview credit balance](/integrations/api/design-studio/tag/email-testing/getInboxPreviewCredits/).
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: 'insufficient inbox preview credits: this request needs 12, the account has 4 available'
              status: '422'
    InboxPreviewNotEnabled:
      description: Inbox previews aren't enabled for your account.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: inbox previews are not enabled for this account
              status: '404'
    InboxPreviewReadRateLimited:
      description: 'Over the App API''s shared limit of 10 requests per second per workspace—the same bucket every call in your workspace that isn''t separately rate limited draws from, writes included. The response carries a `Retry-After` header.

        '
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: rate limited to 10 requests per second
              status: '429'
    InboxPreviewCatalogUnavailable:
      description: The device catalog is temporarily unavailable. This is transient—retry in a moment.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: service unavailable
              status: '503'
    TestSendRateLimited:
      description: 'Rate limited. Every request to this endpoint draws from two buckets: a per-workspace bucket (burst of 20, refilling one every 9 seconds), the same limit the dashboard applies to its own test sends, and a per-IP bucket (burst of 30, refilling one every 10 seconds) that catches one IP address spread across many accounts. Hitting either limit returns this response. The response carries a `Retry-After` header.

        '
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: rate limited
              status: '429'
    InboxPreviewRateLimited:
      description: 'Rate limited to 5 requests per second per workspace—a bucket shared with the Design Studio link, publish, render, preview, and review endpoints, and tighter than the 10 per second reads get, because each call starts a server-side render before it reaches the vendor. The response carries a `Retry-After` header.

        '
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: rate limited to 5 requests per second
              status: '429'
    NotFound:
      description: The requested resource was not found.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: resource not found
              status: '404'
    Unauthorized:
      description: Authentication failed due to a missing or invalid API key.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: unauthorized
              status: '401'
    InboxPreviewRenderUnavailable:
      description: The email or Liquid renderer couldn't be reached. This is transient—retry in a moment.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
          example:
            errors:
            - detail: the email renderer could not be reached; try again in a moment
              status: '503'
  securitySchemes:
    Tracking-API-Key:
      type: http
      scheme: basic
      description: 'The Track API uses a basic authentication scheme. Your credentials are your **Site ID** and your **API key**, **Base-64 encoded** in the format `site_id:api_key`.


        You can find your Site ID and API key on the [Track API Keys page](https://fly.customer.io/settings/api_credentials).

        '
    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/whatsapp`, `/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.
x-tagGroups:
- name: Track API v2
  tags:
  - track_v2
  - Object Schemas
  - Person Schemas
  - Deliveries
- name: Track API
  tags:
  - trackOverview
  - trackJsOrBackend
  - trackLimit
  - trackRegion
  - Track Customers
  - Track Events
  - Forms
  - Track Segments
  - Track v1 Overview
- name: App API
  tags:
  - appOverview
  - appLimit
  - appAuth
  - Activities
  - Automations
  - Broadcasts
  - Collections
  - Customers
  - Data Index
  - ESP Suppression
  - Exports
  - Imports
  - Info
  - Live Notifications
  - Messages
  - Newsletters
  - Opt-outs
  - Reporting Webhooks
  - Segments
  - Sender Identities
  - Snippets
  - Subscription Center
  - Transactional
  - Workspaces
  - Send Messages
  - Objects
  - Newsletter Variants
  - Newsletter Metrics
  - Assets
- name: Design Studio API
  tags:
  - Folders
  - Components
  - Emails
  - Email link and publish
  - Email testing
  - SMS
  - SMS link and publish