matrix-spec/data/api/client-server/mutual_rooms.yaml

# Copyright 2026 Logan Devine <logan@zirco.dev>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
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#     http://www.apache.org/licenses/LICENSE-2.0
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# distributed under the License is distributed on an "AS IS" BASIS,
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openapi: 3.1.0
info:
  title: Matrix Client-Server Mutual Rooms API
  version: 1.0.0
paths:
  /mutual_rooms:
    get:
      summary: Get the list of rooms that the user shares with another user.
      description: |-
        Get the list of rooms that the user shares with another user. The
        server will return a list of room IDs that the user shares with the
        specified `user_id`.
      operationId: getMutualRooms
      security:
        - accessTokenQuery: []
        - accessTokenBearer: []
      parameters:
        - in: query
          name: user_id
          required: true
          description: The MXID of the user to check for mutual rooms with.
          example: "@alice:example.com"
          schema:
            type: string
            format: mx-user-id
            pattern: "^@"
        - in: query
          name: from
          required: false
          description: |-
            A pagination token from a previous result. This should be a `next_batch` result from
            a previous call to this endpoint. If not provided, the server will return the first
            batch of results.
          example: next_batch_token
          schema:
            type: string
      responses:
        "200":
          description: |-
            A list of room IDs that the user shares with the specified user.
            If the provided `user_id` is not a valid user, the server MUST return an empty list of rooms.
          content:
            application/json:
              schema:
                type: object
                required:
                  - joined
                  - count
                properties:
                  joined:
                    type: array
                    description: |-
                      A list of room IDs where both the authenticated user and `user_id` have a
                      membership of type `join`.
                    items:
                      type: string
                      format: mx-room-id
                      pattern: "^!"
                      example: "!OGEhHVWSdvArJzumhm:matrix.org"
                  count:
                    type: integer
                    description: |-
                      The number of such rooms. This is the total count even if the response is
                      batched and `joined` doesn't include all rooms. This MAY be inaccurate
                      if the server is unable to calculate the exact number of rooms.
                    example: 1
                  next_batch:
                    type: string
                    description: |-
                      A pagination token to retrieve the next batch of results. This will be absent
                      if there are no more results to return.
                    example: next_batch_token

        "400":
          description: |-
            Part of the request was invalid. The `from` token provided was invalid or expired,
            the `user_id` parameter was missing, [non-compliant](/appendices/#historical-user-ids),
            or was the sender's own user ID.
          content:
            application/json:
              schema:
                $ref: definitions/errors/error.yaml
              examples:
                response:
                  value: {
                    "errcode": "M_INVALID_PARAM",
                    "error": "The user ID provided was invalid"
                  }
        "429":
          description: This request was rate-limited.
          content:
            application/json:
              schema:
                $ref: definitions/errors/rate_limited.yaml
      tags:
        - Mutual Rooms
servers:
  - url: "{protocol}://{hostname}{basePath}"
    variables:
      protocol:
        enum:
          - http
          - https
        default: https
      hostname:
        default: localhost:8008
      basePath:
        default: /_matrix/client/v1
components:
  securitySchemes:
    accessTokenQuery:
      $ref: definitions/security.yaml#/accessTokenQuery
    accessTokenBearer:
      $ref: definitions/security.yaml#/accessTokenBearer