Real-time API
Stream audio over a WebSocket and receive transcripts as the user speaks.
The Real-time API transcribes audio as it arrives, over a single WebSocket connection that can carry many turns. It suits live audio: voice agents, call handling, or any interface that shows the transcript while the user is still speaking.
This API is served by deployments provisioned for real-time streaming. A deployment answers on one API only, so if yours was provisioned for synchronous transcription its id will not accept a WebSocket connection here — use the Sync API instead. Ask the Blynt team if you are unsure which one you have.
The current production API runs in manual turn-taking mode: the client explicitly brackets each turn with start_turn and end_turn. If you are new here, read the Session flow first for the end-to-end walkthrough, then use this reference for the exact schemas. The Stream a local audio file quickstart is a practical Python integration you can run right away.
The Real-time API accepts fr, en, pt, de, es, it.
Messages
Client → Server (JSON text frames, plus binary audio frames):
| Message | Type | Purpose | Documented in |
|---|---|---|---|
start_session | JSON | First message; sets language, turn-taking mode, and optional session-level biasing (sessionContext). | Client Session API |
| audio bytes | raw | Binary frames of 16 kHz mono int16 PCM audio for the active turn. | Client Session API |
start_turn | JSON | Marks the start of a turn; optionally carries turn-level biasing (turnContext). | Client Turn Control API |
end_turn | JSON | Marks the end of the current turn. | Client Turn Control API |
Server → Client (JSON text frames):
| Message | Type | Purpose | Documented in |
|---|---|---|---|
session_started | JSON | Acknowledges the session and returns its id. | Server API |
turn_started | JSON | A turn has started. | Server API |
turn_partial | JSON | Incremental transcript decoded so far. | Server API |
turn_ended | JSON | The turn ended; contains the final transcript. | Server API |
error | JSON | An error occurred; the connection is closed afterwards. | Errors |
Reference pages
Session flow
End-to-end, message-by-message walkthrough of a session.
Client Session API
Connection, authentication, start_session, and audio bytes.
Client Turn Control API
start_turn (with turn-level biasing) and end_turn.
Server API
session_started, turn_started, turn_partial, and turn_ended.
Errors
The error message the server sends before closing the connection.