openapi: 3.1.0
info:
  title: Basecamp Authorization Messages API
  description: The Basecamp API is a REST API that provides programmatic access to Basecamp's project management and team communication platform. It enables developers to manage projects, to-do lists, messages, documents, schedules, campfires, uploads, card tables, templates, and team members across Basecamp accounts. The API uses OAuth 2.0 for authentication and returns JSON responses, with all requests scoped to an account ID in the base URL path. Resources include projects, people, to-dos, message boards, documents, card tables, campfires, questionnaires, and webhooks, covering the full breadth of Basecamp's collaboration toolset.
  version: '1.0'
  contact:
    name: Basecamp Developer Support
    url: https://github.com/basecamp/bc3-api
  termsOfService: https://basecamp.com/terms
servers:
- url: https://3.basecampapi.com/{accountId}
  description: Production Server
  variables:
    accountId:
      description: Your Basecamp account ID
      default: '999999999'
security:
- bearerAuth: []
tags:
- name: Messages
  description: Manage messages on message boards
paths:
  /message_boards/{messageBoardId}/messages.json:
    get:
      operationId: listMessages
      summary: List messages
      description: Returns a paginated list of active messages in the specified message board. Messages can be sorted by created_at or updated_at.
      tags:
      - Messages
      parameters:
      - $ref: '#/components/parameters/MessageBoardId'
      - name: sort
        in: query
        description: Sort field.
        required: false
        schema:
          type: string
          enum:
          - created_at
          - updated_at
      - name: direction
        in: query
        description: Sort direction.
        required: false
        schema:
          type: string
          enum:
          - asc
          - desc
      responses:
        '200':
          description: List of messages
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/Message'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
    post:
      operationId: createMessage
      summary: Create a message
      description: Creates a new message in the specified message board. Set status to "active" to publish immediately; otherwise the message is saved as a draft.
      tags:
      - Messages
      parameters:
      - $ref: '#/components/parameters/MessageBoardId'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/MessageCreateRequest'
      responses:
        '201':
          description: Message created
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Message'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /messages/{messageId}.json:
    get:
      operationId: getMessage
      summary: Get a message
      description: Returns the message with the given ID.
      tags:
      - Messages
      parameters:
      - $ref: '#/components/parameters/MessageId'
      responses:
        '200':
          description: Message details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Message'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
    put:
      operationId: updateMessage
      summary: Update a message
      description: Updates the subject, content, or category of the specified message.
      tags:
      - Messages
      parameters:
      - $ref: '#/components/parameters/MessageId'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/MessageUpdateRequest'
      responses:
        '200':
          description: Updated message
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Message'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
components:
  schemas:
    Recording:
      type: object
      description: A generic recording object representing any Basecamp content resource such as a message, to-do, document, comment, or upload.
      properties:
        id:
          type: integer
          description: Recording ID
        status:
          type: string
          description: Recording status
          enum:
          - active
          - archived
          - trashed
        visible_to_clients:
          type: boolean
          description: Whether this recording is visible to client users
        created_at:
          type: string
          format: date-time
          description: Timestamp when the recording was created
        updated_at:
          type: string
          format: date-time
          description: Timestamp when the recording was last updated
        title:
          type: string
          description: Title or summary of the recording
        inherits_status:
          type: boolean
          description: Whether this recording inherits its status from a parent
        type:
          type: string
          description: Recording type (e.g., Message, Todo, Document)
        url:
          type: string
          format: uri
          description: API URL for this recording
        app_url:
          type: string
          format: uri
          description: Web URL for this recording
        bucket:
          $ref: '#/components/schemas/BucketRef'
        creator:
          $ref: '#/components/schemas/PersonRef'
    PersonRef:
      type: object
      description: Minimal reference to a Basecamp person
      properties:
        id:
          type: integer
          description: Person ID
        attachable_sgid:
          type: string
          description: Signed global ID for attaching this person
        name:
          type: string
          description: Full name
        email_address:
          type: string
          format: email
          description: Email address
        personable_type:
          type: string
          description: Type of personable (User, Client, etc.)
        title:
          type: string
          description: Job title
        bio:
          type: string
          description: Short biography
        location:
          type: string
          description: Location string
        created_at:
          type: string
          format: date-time
          description: Account creation timestamp
        updated_at:
          type: string
          format: date-time
          description: Last update timestamp
        admin:
          type: boolean
          description: Whether the person is an account administrator
        owner:
          type: boolean
          description: Whether the person is the account owner
        client:
          type: boolean
          description: Whether the person is a client user
        employee:
          type: boolean
          description: Whether the person is an employee
        time_zone:
          type: string
          description: IANA time zone name
        avatar_url:
          type: string
          format: uri
          description: URL to the person's avatar image
        company:
          type: object
          description: Company the person belongs to
          properties:
            id:
              type: integer
              description: Company ID
            name:
              type: string
              description: Company name
    BucketRef:
      type: object
      description: Reference to the project (bucket) that contains a resource
      properties:
        id:
          type: integer
          description: Project ID
        name:
          type: string
          description: Project name
        type:
          type: string
          description: Resource type, always "Project"
        url:
          type: string
          format: uri
          description: API URL for the project
        app_url:
          type: string
          format: uri
          description: Web URL for the project
    MessageCreateRequest:
      type: object
      required:
      - subject
      properties:
        subject:
          type: string
          description: Message subject (title)
        content:
          type: string
          description: Message body in HTML format
        status:
          type: string
          description: Set to "active" to publish immediately
          enum:
          - active
          - draft
        category_id:
          type: integer
          description: Optional message category ID
        subscriptions:
          type: array
          description: Person IDs to notify about this message
          items:
            type: integer
    MessageUpdateRequest:
      type: object
      properties:
        subject:
          type: string
          description: Updated message subject
        content:
          type: string
          description: Updated message body in HTML format
        category_id:
          type: integer
          description: Updated message category ID
    Message:
      allOf:
      - $ref: '#/components/schemas/Recording'
      - type: object
        properties:
          subject:
            type: string
            description: Message subject/title
          content:
            type: string
            description: HTML-formatted message body
          comments_count:
            type: integer
            description: Number of comments on this message
          comments_url:
            type: string
            format: uri
            description: API URL to list comments
          boosts_count:
            type: integer
            description: Number of boosts (reactions) on this message
    Error:
      type: object
      properties:
        error:
          type: string
          description: Human-readable error message
  responses:
    BadRequest:
      description: Bad request — missing required fields or invalid values
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    Unauthorized:
      description: Unauthorized — missing or invalid Bearer token
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    NotFound:
      description: Not found — the requested resource does not exist
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  parameters:
    MessageId:
      name: messageId
      in: path
      required: true
      description: Unique identifier of the message
      schema:
        type: integer
    MessageBoardId:
      name: messageBoardId
      in: path
      required: true
      description: Unique identifier of the message board
      schema:
        type: integer
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: 'OAuth 2.0 Bearer token obtained via the Basecamp authorization code flow at launchpad.37signals.com. Include as "Authorization: Bearer {token}" in all requests.'
externalDocs:
  description: Basecamp API Documentation
  url: https://github.com/basecamp/bc3-api