Loli 2.0

Realtime STT (Auto)

Choose automatic VAD or manual commits for a continuous PCM16 microphone stream.

WS/api/public/v1/stt/ws?token=<stt_key>

On this page

Authorization
Request
Response
Errors

Code examples

const ws = new WebSocket(
  "wss://studio.evomlabs.com/api/public/v1/stt/ws" +
  "?token=stt_sk_live_YOUR_KEY&language=auto"
);

ws.addEventListener("open", () => {
  ws.send(JSON.stringify({
    type: "start",
    mode: "auto",
    language: "auto",
    sample_rate: 48000,
    format: "pcm_s16le",
  }));
});

ws.addEventListener("message", (event) => {
  const message = JSON.parse(event.data);
  if (message.type === "partial" || message.type === "segment") {
    renderTranscript(message.combined_text);
  }
  if (message.type === "final") {
    renderTranscript(message.text);
  }
  if (message.type === "error") {
    console.error(message.code, message.message);
  }
});

// Send PCM16 frames with ws.send(arrayBuffer).
function stopTranscription() {
  if (ws.readyState === WebSocket.OPEN) {
    ws.send(JSON.stringify({ type: "stop" }));
  }
}

Authorization

Bearer credential

Send the credential in the Authorization header. Account and voice keys are accepted only where the endpoint contract permits them.

Security

The key travels in the query string, so it is exposed if the connection is opened from client-side code. Open the socket from your own server, over TLS. A missing or wrong key emits the error code unauthorized and the socket closes with code 1008.

Request

Field	Type	Required	Default	Description
`type`	"start"	Yes	-	Use start.
`mode`	"auto" \| "manual"	No	`auto`	auto uses server VAD; manual waits for a client commit.
`language`	string	No	`auto`	One of the language modes listed above.
`sample_rate`	integer	No	`16000`	Integer binary-input rate from 8,000 to 192,000 Hz.
`format`	"pcm_s16le"	No	`pcm_s16le`	Exactly pcm_s16le: mono signed 16-bit little-endian PCM.
`session_id`	string	No	`Server generated`	Optional client-provided identifier.

Send stop before closing

Send a stop message to end the session. The server then emits final, followed by closed. Closing the socket without sending stop cancels the session and does not guarantee a final transcript.

Response

Events

// Server to client

{ "type": "started", "session_id": "session_id", "mode": "auto", "language": "auto",
  "sample_rate": 16000, "provider": "loli-asr", "model": "Loli 2.0" }

{ "type": "partial", "index": 0, "text": "live window text",
  "committed_text": "", "live_text": "live utterance text",
  "combined_text": "live utterance text", "is_final": false,
  "language": "vi", "latency_ms": 210 }

{ "type": "segment", "index": 0, "text": "committed utterance",
  "committed_text": "committed utterance", "live_text": "",
  "combined_text": "committed utterance", "is_final": true,
  "language": "vi", "latency_ms": 350 }

{ "type": "final", "text": "Toàn bộ transcript", "language": "vi",
  "is_final": true, "provider": "loli-asr", "model": "Loli 2.0",
  "latency_ms": 4100 }

{ "type": "closed", "session_id": "session_id", "reason": "stopped" }

{ "type": "error", "session_id": "session_id-or-null",
  "message": "Error description", "code": "bad_request" }

Note

A partial can be replaced by a newer partial for the same utterance; a segment commits one utterance at a silence boundary. Use combined_text to display the transcript so far.

Errors

REST failures use the documented error envelope. Handle the error code instead of matching the human-readable message.

Error codes

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