Add a session to the room
**Rate limit: Per room** · **Burst:** 100 · **Refill:** 30 req/s
Add a [room member](/api/room-members). This is the canonical join endpoint.
Members join unmuted by default; pass `"muted": true` to join muted.
The member is identified by its session UUID, the
same identifier `GET /api/v1/rooms/{room_id}/members` returns.
**Triggered webhooks:** `room.member.joined` (deferred, emitted when the underlying media operation completes)
Returns 200 if the session is already in this room (idempotent).
Returns 409 if the session is still mid-join in a different room.
Authentication
AuthorizationBearer
Application auth. Send `Authorization: Bearer <app_uuid>:<api_key>`. See [Authentication](https://voice-platform.docs.buildwithfern.com/api/authentication) for details.
Path parameters
room_id
Room ID
(format {prefix}-room-{uuid}). The UUID portion is lowercase
hexadecimal — uppercase hex is rejected with 400.
Headers
Idempotency-Key
Optional client-generated key for a mutating endpoint. It identifies one method, route, query, content type, and exact raw body within the authenticated app. Reusing it for a different request returns 422. While its record exists, a retry replays the original accepted response when available. Keys are valid for 1 hour. Allowed characters: letters, digits, dot, hyphen, underscore; max 128 characters. See the Idempotency guide.
Request
This endpoint expects an object.
session_uuid
Session UUID of the member to add — the identifier
GET /api/v1/rooms/{room_id}/members returns.
muted
If true, the member joins muted. Omitted or false joins the member unmuted (audible immediately).
Response
Session already joined to this room (idempotent)
room_id
status
Errors
400
Bad Request Error
401
Unauthorized Error
404
Not Found Error
409
Conflict Error
413
Content Too Large Error
415
Unsupported Media Type Error
422
Unprocessable Entity Error
429
Too Many Requests Error
500
Internal Server Error
503
Service Unavailable Error