openapi: 3.2.0
info:
  title: SendHQ Emails and threads API
  version: '2026-08-23'
  description: Send and receive expected email, manage verified domains and hosted templates, and inspect delivery outcomes.
servers:
- url: https://sendhq.cc/api/v1
tags:
- name: Emails and threads
  description: Send, retrieve, search, reply, and inspect delivery events.
paths:
  /emails:
    post:
      operationId: post_emails
      tags:
      - Emails and threads
      summary: Send one email
      description: Send transactional HTML, text, or hosted-template content from a verified workspace domain.
      security:
      - bearerAuth: []
      parameters:
      - name: Idempotency-Key
        in: header
        required: false
        schema:
          type: string
      responses:
        '201':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                  providerMessageId:
                    type: string
                  threadId:
                    type: string
                required:
                - id
                - providerMessageId
                - threadId
                additionalProperties: false
              example:
                id: em_…
                providerMessageId: provider-id
                threadId: em_…
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/RateLimited'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                from:
                  type: string
                to:
                  type: array
                  items:
                    type: string
                    format: email
                subject:
                  type: string
                html:
                  type: string
                text:
                  type: string
              required:
              - from
              - to
              - subject
              - html
              - text
              additionalProperties: false
            example:
              from: Acme <hello@example.com>
              to:
              - customer@example.net
              subject: Welcome aboard
              html: <h1>Welcome</h1><p>Your workspace is ready.</p>
              text: Welcome. Your workspace is ready.
    get:
      operationId: get_emails
      tags:
      - Emails and threads
      summary: List sent and received email
      description: List sent and received email
      security:
      - bearerAuth: []
      parameters:
      - name: direction
        in: query
        required: false
        schema:
          type: string
          enum:
          - in
          - out
      - name: status
        in: query
        required: false
        schema:
          type: string
      - name: domain
        in: query
        required: false
        schema:
          type: string
      - name: inbox_id
        in: query
        required: false
        schema:
          type: string
      - name: from
        in: query
        required: false
        schema:
          type: string
      - name: to
        in: query
        required: false
        schema:
          type: string
      - name: unread
        in: query
        required: false
        schema:
          type: boolean
      - name: after
        in: query
        required: false
        schema:
          type: string
          format: date-time
      - name: before
        in: query
        required: false
        schema:
          type: string
          format: date-time
      - name: query
        in: query
        required: false
        schema:
          type: string
      - name: limit
        in: query
        required: false
        schema:
          type: integer
          minimum: 1
      - name: offset
        in: query
        required: false
        schema:
          type: integer
          minimum: 0
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items: {}
                  count:
                    type: integer
                required:
                - data
                - count
                additionalProperties: false
              example:
                data: []
                count: 0
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/RateLimited'
  /emails/batch:
    post:
      operationId: post_emails_batch
      tags:
      - Emails and threads
      summary: Send up to 100 individualized messages
      description: Send up to 100 individualized messages
      security:
      - bearerAuth: []
      parameters:
      - name: Idempotency-Key
        in: header
        required: false
        schema:
          type: string
      responses:
        '201':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      type: object
                      properties:
                        index:
                          type: integer
                        ok:
                          type: boolean
                        id:
                          type: string
                      required:
                      - index
                      - ok
                      - id
                      additionalProperties: false
                  count:
                    type: integer
                  successful:
                    type: integer
                  failed:
                    type: integer
                required:
                - data
                - count
                - successful
                - failed
                additionalProperties: false
              example:
                data:
                - index: 0
                  ok: true
                  id: em_…
                count: 1
                successful: 1
                failed: 0
        '207':
          description: Successful response with partial outcomes
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      type: object
                      properties:
                        index:
                          type: integer
                        ok:
                          type: boolean
                        id:
                          type: string
                      required:
                      - index
                      - ok
                      - id
                      additionalProperties: false
                  count:
                    type: integer
                  successful:
                    type: integer
                  failed:
                    type: integer
                required:
                - data
                - count
                - successful
                - failed
                additionalProperties: false
              example:
                data:
                - index: 0
                  ok: true
                  id: em_…
                count: 1
                successful: 1
                failed: 0
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/RateLimited'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                emails:
                  type: array
                  items:
                    type: object
                    properties:
                      from:
                        type: string
                      to:
                        type: array
                        items:
                          type: string
                          format: email
                      subject:
                        type: string
                      html:
                        type: string
                      text:
                        type: string
                    required:
                    - from
                    - to
                    - subject
                    - html
                    - text
                    additionalProperties: false
              required:
              - emails
              additionalProperties: false
            example:
              emails:
              - from: Acme <hello@example.com>
                to:
                - customer@example.net
                subject: Welcome aboard
                html: <h1>Welcome</h1><p>Your workspace is ready.</p>
                text: Welcome. Your workspace is ready.
  /emails/{id}:
    get:
      operationId: get_emails_id
      tags:
      - Emails and threads
      summary: Retrieve an email and its attachments
      description: Retrieve an email and its attachments
      security:
      - bearerAuth: []
      parameters:
      - name: id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                  direction:
                    type: string
                  status:
                    type: string
                  attachments:
                    type: array
                    items: {}
                required:
                - id
                - direction
                - status
                - attachments
                additionalProperties: false
              example:
                id: em_…
                direction: out
                status: sent
                attachments: []
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/RateLimited'
    patch:
      operationId: patch_emails_id
      tags:
      - Emails and threads
      summary: Mark an email read or unread
      description: Mark an email read or unread
      security:
      - bearerAuth: []
      parameters:
      - name: id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                  readAt:
                    type: string
                    format: date-time
                required:
                - id
                - readAt
                additionalProperties: false
              example:
                id: em_…
                readAt: '2026-08-23T12:00:00.000Z'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/RateLimited'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                read:
                  type: boolean
              required:
              - read
              additionalProperties: false
            example:
              read: true
    delete:
      operationId: delete_emails_id
      tags:
      - Emails and threads
      summary: Delete a retained email
      description: Delete a retained email
      security:
      - bearerAuth: []
      parameters:
      - name: id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  ok:
                    type: boolean
                required:
                - ok
                additionalProperties: false
              example:
                ok: true
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/RateLimited'
  /emails/{id}/events:
    get:
      operationId: get_emails_id_events
      tags:
      - Emails and threads
      summary: List delivery events for an email
      description: List delivery events for an email
      security:
      - bearerAuth: []
      parameters:
      - name: id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items: {}
                  count:
                    type: integer
                required:
                - data
                - count
                additionalProperties: false
              example:
                data: []
                count: 0
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/RateLimited'
  /threads/{id}:
    get:
      operationId: get_threads_id
      tags:
      - Emails and threads
      summary: Retrieve a conversation chronologically
      description: Retrieve a conversation chronologically
      security:
      - bearerAuth: []
      parameters:
      - name: id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                  data:
                    type: array
                    items: {}
                  count:
                    type: integer
                required:
                - id
                - data
                - count
                additionalProperties: false
              example:
                id: em_…
                data: []
                count: 0
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/RateLimited'
components:
  schemas:
    Error:
      type: object
      required:
      - error
      properties:
        error:
          type: object
          required:
          - message
          - status
          properties:
            message:
              type: string
            status:
              type: integer
            code:
              type:
              - string
              - 'null'
  responses:
    Unauthorized:
      description: Missing or invalid authentication
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    RateLimited:
      description: A usage or reputation limit was reached
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    BadRequest:
      description: Invalid request
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    NotFound:
      description: Resource not found
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: re_…
      description: Workspace API key. Keep it server-side.
    sessionCookie:
      type: apiKey
      in: cookie
      name: sendhq_session_v2
      description: Browser session used for account administration.