Roblox Engine API Messaging API

openapi: 3.0.3
info:
  title: Roblox Open Cloud Assets Messaging API
  description: The Roblox Open Cloud API provides external programmatic access to Roblox platform resources. It enables server-side operations on experiences, places, data stores, memory stores, users, groups, assets, messaging, badges, game passes, and subscriptions. Authentication uses API keys scoped to specific resources. The API is organized into Open Cloud v2, v1, and Legacy tiers with consistent RESTful patterns.
  version: v2
  contact:
    name: Roblox Developer Relations
    url: https://devforum.roblox.com
  termsOfService: https://en.help.roblox.com/hc/en-us/articles/115004647846
  license:
    name: Proprietary
servers:
- url: https://apis.roblox.com
  description: Roblox Open Cloud API
tags:
- name: Messaging
  description: Cross-server messaging service
paths:
  /messaging-service/v1/universes/{universeId}/topics/{topic}:
    post:
      operationId: publishMessage
      summary: Publish Message
      description: Publish a message to a topic in the messaging service. Messages are delivered to all servers in the universe subscribed to the topic.
      tags:
      - Messaging
      security:
      - ApiKeyAuth: []
      parameters:
      - name: universeId
        in: path
        required: true
        schema:
          type: string
      - name: topic
        in: path
        required: true
        schema:
          type: string
        description: The message topic name (max 80 characters)
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/PublishMessageRequest'
      responses:
        '200':
          description: Message published
        '401':
          $ref: '#/components/responses/Unauthorized'
        '403':
          $ref: '#/components/responses/Forbidden'
components:
  responses:
    Unauthorized:
      description: Authentication failed
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    Forbidden:
      description: Insufficient permissions for this resource
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  schemas:
    Error:
      type: object
      properties:
        code:
          type: integer
        message:
          type: string
        details:
          type: array
          items:
            type: object
    PublishMessageRequest:
      type: object
      required:
      - message
      properties:
        message:
          type: string
          description: The message content (max 1kB)
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: x-api-key
      description: Roblox Open Cloud API key scoped to specific resources