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

# Publish a message to a channel

> Publishes a single message to the named channel. Requires scope: realtime:publish



## OpenAPI

````yaml /api-specs/services.json post /realtime/v1/channels/{channel}/messages
openapi: 3.1.0
info:
  title: Voyant Cloud REST API
  version: 1.0.0
  description: >-
    Public REST API for Voyant Cloud products: Vault, SMS, Email, Verification,
    Video, Realtime, and Browser. All requests authenticate with an API token
    passed as an HTTP bearer token in the Authorization header. Each operation
    requires a specific token scope, documented in the operation description.
servers:
  - url: https://api.voyant.travel
    description: Production
security:
  - bearerAuth: []
tags:
  - name: Vault
    description: >-
      Encrypted secret storage and envelope/per-call cryptography scoped to an
      organization vault.
  - name: SMS
    description: Send SMS messages and inspect message history and phone numbers.
  - name: Email
    description: Send transactional email and inspect message history.
  - name: Verification
    description: >-
      Start and check one-time-code verifications across SMS, call, email, and
      WhatsApp.
  - name: Video
    description: >-
      Upload, manage, caption, and watermark videos, and mint signed playback
      tokens.
  - name: Realtime
    description: >-
      Publish messages to realtime channels, inspect history and presence, and
      mint short-lived subscriber tokens.
  - name: Browser
    description: >-
      Headless browser rendering, scraping, structured extraction, crawling, and
      interactive sessions.
paths:
  /realtime/v1/channels/{channel}/messages:
    post:
      tags:
        - Realtime
      summary: Publish a message to a channel
      description: >-
        Publishes a single message to the named channel. Requires scope:
        realtime:publish
      operationId: publishRealtimeMessage
      parameters:
        - $ref: '#/components/parameters/RealtimeChannel'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/PublishRealtimeMessageInput'
      responses:
        '200':
          description: Published message
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RealtimeMessageSummary'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '403':
          $ref: '#/components/responses/Forbidden'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/TooManyRequests'
        '500':
          $ref: '#/components/responses/ServerError'
        '503':
          $ref: '#/components/responses/ServiceUnavailable'
      x-codeSamples:
        - lang: typescript
          label: SDK
          source: >-
            import { createVoyantCloudClient } from "@voyant-travel/cloud-sdk";


            const cloud = createVoyantCloudClient({ apiKey:
            process.env.VOYANT_API_KEY });


            const message = await cloud.realtime.publish("<channel>", {
              "event": "order.updated",
              "data": "<string>"
            });
        - lang: bash
          label: cURL
          source: |-
            curl --request POST \
              --url https://api.voyant.travel/realtime/v1/channels/<channel>/messages \
              --header 'Authorization: Bearer <token>' \
              --header 'Content-Type: application/json' \
              --data '{
              "event": "order.updated",
              "data": "<string>"
            }'
        - lang: javascript
          label: Node
          source: >-
            const response = await
            fetch("https://api.voyant.travel/realtime/v1/channels/<channel>/messages",
            {
              method: "POST",
              headers: {
                "Content-Type": "application/json",
                "Authorization": "Bearer <token>"
              },
              body: JSON.stringify({
                "event": "order.updated",
                "data": "<string>"
              }),
            });


            const data = await response.json();
        - lang: python
          label: Python
          source: |-
            import requests

            response = requests.post(
                "https://api.voyant.travel/realtime/v1/channels/<channel>/messages",
                headers={
                    "Authorization": "Bearer <token>"
                },
                json={
                    "event": "order.updated",
                    "data": "<string>"
                }
            )

            data = response.json()
components:
  parameters:
    RealtimeChannel:
      name: channel
      in: path
      required: true
      schema:
        type: string
      example: orders:org_123
  schemas:
    PublishRealtimeMessageInput:
      type: object
      required:
        - event
      properties:
        event:
          type: string
          description: Event name delivered to subscribers.
          example: order.updated
        data:
          description: JSON-serializable payload delivered as-is to subscribers.
    RealtimeMessageSummary:
      type: object
      required:
        - id
        - channel
        - event
        - data
        - publishedAt
      properties:
        id:
          type: string
        channel:
          type: string
        event:
          type: string
        data: {}
        publishedAt:
          type: string
          format: date-time
    Error:
      type: object
      properties:
        error:
          type: string
    RateLimitError:
      type: object
      required:
        - error
      properties:
        error:
          type: string
        retryAfterMs:
          type: integer
          description: Milliseconds to wait before retrying.
  responses:
    BadRequest:
      description: Invalid request
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    Unauthorized:
      description: Authentication is missing, invalid, revoked, or expired.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    Forbidden:
      description: The API token does not include a scope required for this operation.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    NotFound:
      description: Resource not found
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    TooManyRequests:
      description: Rate limit exceeded.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/RateLimitError'
    ServerError:
      description: An unexpected error occurred.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    ServiceUnavailable:
      description: >-
        A required dependency (for example the platform database) is not
        available.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: >-
        Voyant Cloud API token, passed as `Authorization: Bearer <token>`. Each
        token carries a fixed set of scopes; an operation rejects tokens missing
        its required scope.

````