matrix-spec-proposals/api/client-server/v1/membership.yaml

swagger: '2.0'
info:
  title: "Matrix Client-Server v1 Room Membership API"
  version: "1.0.0"
host: localhost:8008
schemes:
  - https
  - http
basePath: /_matrix/client/api/v1
consumes:
  - application/json
produces:
  - application/json
securityDefinitions:
  accessToken:
    type: apiKey
    description: The user_id or application service access_token
    name: access_token
    in: query
paths:
  "/rooms/{roomId}/join":
    post:
      summary: Start the requesting user participating in a particular room.
      description: |-
        This API starts a user participating in a particular room, if that user
        is allowed to participate in that room. After this call, the client is
        allowed to see all current state events in the room, and all subsequent
        events associated with the room until the user leaves the room.

        After a user has joined a room, the room will appear as an entry in the
        response of the |initialSync| API.
      security:
        - accessToken: []
      parameters:
        - in: path
          type: string
          name: roomId
          description: The room identifier or room alias to join.
          required: true
          x-example: "#monkeys:matrix.org"
      responses:
        200:
          description: |-
            The room has been joined.

            The joined room ID must be returned in the room_id field.
          examples:
            application/json: |-
              {"room_id": "!d41d8cd:matrix.org"}
          schema:
            type: object  # empty json object
        403:
          description: |-
            You do not have permission to join the room. A meaningful ``errcode`` and description error text will be returned. Example reasons for rejection are:
              - The room is invite-only and the user was not invited.
              - The user has been banned from the room.
          examples:
            application/json: |-
              {"errcode": "M_FORBIDDEN", "error": "You are not invited to this room."}
        429:
          description: This request was rate-limited.
          schema:
            "$ref": "definitions/error.yaml"
      x-alias:
        canonical-link: "post-matrix-client-api-v1-rooms-roomid-join"
        aliases:
          - /join/{roomId}