> ## Documentation Index
> Fetch the complete documentation index at: https://docs.contiguity.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Cancel a queued send

> Cancel a queued SMS, iMessage, or WhatsApp send

<Warning>
  This does not unsend a message. If the send is already in flight, it may still go out. Messages whose delivery is already confirmed return `400`.
</Warning>

<Note>
  Repeat calls are idempotent — cancelling the same `msg_id` again still returns `cancelled: true`.
</Note>

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/>


## OpenAPI

````yaml openapi-conversations POST /cancel/{msg_id}
openapi: 3.0.0
info:
  version: v2026.8.18
  title: Conversations API
servers:
  - url: https://api.contiguity.com/conversations
security: []
paths:
  /cancel/{msg_id}:
    post:
      parameters:
        - schema:
            type: string
            description: >-
              Contiguity message ID (text_… or imsg_…), the same id returned
              when the message was sent.
            example: text_u98sZQCVsLvgBq80
          required: true
          description: >-
            Contiguity message ID (text_… or imsg_…), the same id returned when
            the message was sent.
          name: msg_id
          in: path
      responses:
        '200':
          description: >-
            Cancel a queued SMS, iMessage, or fast-track send. Does not unsend a
            message already in flight. If the message was recently retried,
            cancellation applies when it becomes up for retry again (up to about
            an hour). Idempotent.
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                    example: req_xxxxxxxxxxxxxxxx
                  timestamp:
                    type: number
                    example: 1787072276500
                  api_version:
                    type: string
                    example: v2026.8.18
                  object:
                    type: string
                    example: response
                  data:
                    type: object
                    properties:
                      cancelled:
                        type: boolean
                        description: >-
                          Whether the cancel was accepted. True even if you
                          already cancelled this id.
                        example: true
                      msg_id:
                        type: string
                        description: The cancelled message ID.
                        example: text_u98sZQCVsLvgBq80
                    required:
                      - cancelled
                      - msg_id
                required:
                  - id
                  - timestamp
                  - api_version
                  - object
                  - data
        '400':
          description: Bad Request
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                    example: err_xxxxxxxxxxxxxxxx
                  timestamp:
                    type: number
                    example: 1787072276500
                  api_version:
                    type: string
                    example: v2026.8.18
                  object:
                    type: string
                    example: error
                  data:
                    type: object
                    properties:
                      error:
                        type: string
                        example: Bad Request
                      status:
                        type: number
                        example: 400
                    required:
                      - error
                      - status
                required:
                  - id
                  - timestamp
                  - api_version
                  - object
                  - data
        '401':
          description: Unauthorized
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                    example: err_xxxxxxxxxxxxxxxx
                  timestamp:
                    type: number
                    example: 1787072276500
                  api_version:
                    type: string
                    example: v2026.8.18
                  object:
                    type: string
                    example: error
                  data:
                    type: object
                    properties:
                      error:
                        type: string
                        example: Unauthorized
                      status:
                        type: number
                        example: 401
                    required:
                      - error
                      - status
                required:
                  - id
                  - timestamp
                  - api_version
                  - object
                  - data
        '403':
          description: Forbidden
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                    example: err_xxxxxxxxxxxxxxxx
                  timestamp:
                    type: number
                    example: 1787072276500
                  api_version:
                    type: string
                    example: v2026.8.18
                  object:
                    type: string
                    example: error
                  data:
                    type: object
                    properties:
                      error:
                        type: string
                        example: Forbidden
                      status:
                        type: number
                        example: 403
                    required:
                      - error
                      - status
                required:
                  - id
                  - timestamp
                  - api_version
                  - object
                  - data
        '500':
          description: Internal Server Error
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                    example: err_xxxxxxxxxxxxxxxx
                  timestamp:
                    type: number
                    example: 1787072276500
                  api_version:
                    type: string
                    example: v2026.8.18
                  object:
                    type: string
                    example: error
                  data:
                    type: object
                    properties:
                      error:
                        type: string
                        example: Internal Server Error
                      status:
                        type: number
                        example: 500
                    required:
                      - error
                      - status
                required:
                  - id
                  - timestamp
                  - api_version
                  - object
                  - data
      security:
        - bearerAuth: []
components:
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer

````