ElevenLabsSTT

Defined in: src/providers/stt/elevenlabs/ElevenLabsSTT.ts:317

ElevenLabs STT provider for real-time streaming speech-to-text via WebSocket.

Remarks

This provider establishes a WebSocket connection to the ElevenLabs Scribe V2 real-time STT API (or a proxy server). Audio chunks are base64-encoded and sent as JSON input_audio_chunk messages. Transcription results are received as partial_transcript and committed_transcript messages.

The lifecycle is:

1. Construct with ElevenLabsSTTConfig
2. Call initialize() to validate configuration and build the WebSocket URL
3. Call connect() to open the WebSocket and wait for session_started
4. Call sendAudio() to stream audio chunks for transcription
5. Call disconnect() to close the WebSocket
6. Call dispose() to release all resources

Audio flow: Microphone -> AudioCapture -> sendAudio(chunk) -> WebSocket -> Scribe V2

Example

import { ElevenLabsSTT } from 'composite-voice';

const stt = new ElevenLabsSTT({
  proxyUrl: 'http://localhost:3001/api/proxy/elevenlabs',
  model: 'scribe_v2_realtime',
  commitStrategy: 'vad',
  audioFormat: 'pcm_16000',
});

await stt.initialize();
await stt.connect();

stt.onTranscription((result) => {
  if (result.isFinal) {
    console.log('Final:', result.text);
  } else {
    console.log('Partial:', result.text);
  }
});

// Stream audio chunks from microphone...
stt.sendAudio(audioChunk);

await stt.disconnect();

See

• LiveSTTProvider - The base class this provider extends.
• ElevenLabsSTTConfig - Configuration options for this provider.
• WebSocketManager - The WebSocket manager used for connection handling.

Extends

• LiveSTTProvider

Constructors

Constructor

new ElevenLabsSTT(config, logger?): ElevenLabsSTT;

Defined in: src/providers/stt/elevenlabs/ElevenLabsSTT.ts:331

Creates a new ElevenLabsSTT provider instance.

Parameters

Returns

ElevenLabsSTT

Overrides

LiveSTTProvider.constructor

Properties

Accessors

isProxyMode

Get Signature

get protected isProxyMode(): boolean;

Defined in: src/providers/base/BaseProvider.ts:286

Whether the provider is in proxy mode.

Returns

boolean

true when proxyUrl is set.

Inherited from

LiveSTTProvider.isProxyMode

Methods

assertAuth()

protected assertAuth(): void;

Defined in: src/providers/base/BaseProvider.ts:272

Validate that auth is configured (either apiKey or proxyUrl).

Returns

void

Remarks

Call this in onInitialize() for any provider that requires external authentication. Native providers (NativeSTT, NativeTTS) and in-browser providers (WebLLM) should NOT call this method.

Throws

ProviderInitializationError Thrown when neither apiKey nor proxyUrl is set.

Inherited from

LiveSTTProvider.assertAuth

assertReady()

protected assertReady(): void;

Defined in: src/providers/base/BaseProvider.ts:255

Guard that throws if the provider has not been initialized.

Returns

void

Remarks

Call at the start of any method that requires the provider to be ready.

Throws

Error Thrown with a descriptive message when initialized is false.

Inherited from

LiveSTTProvider.assertReady

connect()

connect(): Promise<void>;

Defined in: src/providers/stt/elevenlabs/ElevenLabsSTT.ts:479

Opens a WebSocket connection and waits for the session_started message.

Returns

Promise<void>

Remarks

Establishes a WebSocket connection to the ElevenLabs real-time STT endpoint (or proxy). The connect promise does not resolve until the server sends a session_started message, ensuring the session is fully initialized before audio streaming begins.

Auto-reconnect is disabled because each STT session is stateful and cannot be resumed after disconnection.

Throws

ProviderConnectionError if the connection fails or times out.

Overrides

LiveSTTProvider.connect

disconnect()

disconnect(): Promise<void>;

Defined in: src/providers/stt/elevenlabs/ElevenLabsSTT.ts:777

Disconnects from the ElevenLabs WebSocket.

Returns

Promise<void>

Remarks

Sends a final commit message to flush any buffered audio, waits briefly for remaining transcription results, then gracefully closes the WebSocket connection and releases the WebSocketManager instance.

Throws

Rethrows any error that occurs during disconnection.

Overrides

LiveSTTProvider.disconnect

dispose()

dispose(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:154

Clean up resources and dispose of the provider.

Returns

Promise<void>

Remarks

Delegates to the subclass hook onDispose and resets the initialized flag. If the provider is not initialized, the call is a no-op.

Throws

Re-throws any error raised by onDispose.

Inherited from

LiveSTTProvider.dispose

emitTranscription()

protected emitTranscription(result): void;

Defined in: src/providers/base/BaseSTTProvider.ts:206

Emit a transcription result to the registered callback.

Parameters

Returns

void

Remarks

Subclasses call this method whenever transcribed text is available. If no callback has been registered via onTranscription, the result is logged as a warning and dropped.

Inherited from

LiveSTTProvider.emitTranscription

getConfig()

getConfig(): STTProviderConfig;

Defined in: src/providers/base/BaseSTTProvider.ts:225

Get a shallow copy of the current STT configuration.

Returns

STTProviderConfig

A new STTProviderConfig object.

Inherited from

LiveSTTProvider.getConfig

initialize()

initialize(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:127

Initialize the provider, making it ready for use.

Returns

Promise<void>

Remarks

Calls the subclass hook onInitialize. If the provider has already been initialized the call is a no-op.

Throws

ProviderInitializationError Thrown when onInitialize rejects. The original error is wrapped with the provider class name for diagnostics.

Inherited from

LiveSTTProvider.initialize

isFinal()

isFinal(result): boolean;

Defined in: src/providers/base/BaseSTTProvider.ts:174

Is this a final segment (but not necessarily utterance-complete)?

Parameters

Returns

boolean

true when this is a final segment.

Remarks

A final segment represents committed text, but multi-segment providers (e.g., Deepgram) may emit several final segments for a single utterance. Only the last one will have isUtteranceComplete return true.

Inherited from

LiveSTTProvider.isFinal

isInterim()

isInterim(result): boolean;

Defined in: src/providers/base/BaseSTTProvider.ts:159

Is this an interim (partial, non-final) result?

Parameters

Returns

boolean

true when this is an interim result.

Remarks

Interim results update as the user speaks and are replaced by subsequent results. Useful for display but not for triggering downstream processing.

Inherited from

LiveSTTProvider.isInterim

isPreflight()

isPreflight(result): boolean;

Defined in: src/providers/base/BaseSTTProvider.ts:144

Is this a preflight/eager end-of-turn signal?

Parameters

Returns

boolean

true when this is a preflight signal.

Remarks

Used by the eager LLM pipeline for speculative generation. Only providers with preflight support (e.g., Deepgram Flux) need to override this.

Inherited from

LiveSTTProvider.isPreflight

isReady()

isReady(): boolean;

Defined in: src/providers/base/BaseProvider.ts:178

Check whether the provider has been initialized and is ready.

Returns

boolean

true when initialize has completed successfully and dispose has not yet been called.

Inherited from

LiveSTTProvider.isReady

isUtteranceComplete()

isUtteranceComplete(result): boolean;

Defined in: src/providers/base/BaseSTTProvider.ts:129

Is this result a complete utterance ready for LLM processing?

Parameters

Returns

boolean

true when the utterance is complete.

Remarks

The orchestrator calls this to decide when to send transcribed text to the LLM. Concrete providers override this when they have domain- specific endpointing logic (e.g., DeepgramSTT checks speech_final).

Inherited from

LiveSTTProvider.isUtteranceComplete

isWebSocketConnected()

isWebSocketConnected(): boolean;

Defined in: src/providers/stt/elevenlabs/ElevenLabsSTT.ts:835

Checks whether the WebSocket connection to ElevenLabs is currently active.

Returns

boolean

true if the WebSocket is connected, false otherwise.

onConfigUpdate()

protected onConfigUpdate(_config): void;

Defined in: src/providers/base/BaseProvider.ts:242

Hook called after updateConfig merges new values.

Parameters

Returns

void

Remarks

The default implementation is a no-op. Override in subclasses to react to runtime configuration changes (e.g. reconnect with a new API key).

Inherited from

LiveSTTProvider.onConfigUpdate

onDispose()

protected onDispose(): Promise<void>;

Defined in: src/providers/stt/elevenlabs/ElevenLabsSTT.ts:376

Disposes the provider, disconnecting and releasing resources.

Returns

Promise<void>

Overrides

LiveSTTProvider.onDispose

onInitialize()

protected onInitialize(): Promise<void>;

Defined in: src/providers/stt/elevenlabs/ElevenLabsSTT.ts:346

Validates configuration and builds the WebSocket URL with query parameters.

Logs a debug warning if none of apiKey, token, or proxyUrl is configured.

Returns

Promise<void>

Overrides

LiveSTTProvider.onInitialize

onTranscription()

onTranscription(callback): void;

Defined in: src/providers/base/BaseSTTProvider.ts:191

Register a callback to receive transcription results.

Parameters

Returns

void

Remarks

All STT providers — regardless of transport — deliver text through this callback. CompositeVoice registers it during pipeline setup so that transcription results flow into the conversation manager and, ultimately, the LLM provider.

Inherited from

LiveSTTProvider.onTranscription

processAudio()

processAudio(chunk): void;

Defined in: src/providers/base/LiveSTTProvider.ts:140

Process a raw audio chunk by sending it over the WebSocket.

Parameters

Returns

void

Remarks

Legacy alias for sendAudio. Delegates to sendAudioToSocket.

Inherited from

LiveSTTProvider.processAudio

resolveApiKey()

protected resolveApiKey(): string;

Defined in: src/providers/base/BaseProvider.ts:325

Resolve the API key for this provider.

Returns

string

The configured API key, or 'proxy' in proxy mode.

Remarks

Returns 'proxy' in proxy mode so that SDK clients (which require a non-empty API key string) can be instantiated without the real key.

Inherited from

LiveSTTProvider.resolveApiKey

resolveAuthHeader()

protected resolveAuthHeader(defaultAuthType?): string | undefined;

Defined in: src/providers/base/BaseProvider.ts:366

Resolve Authorization header value for the configured auth type.

Parameters

Returns

string | undefined

The Authorization header value, or undefined in proxy mode.

Remarks

Returns the header value for REST or server-side WebSocket connections:

• 'token' → 'Token <apiKey>'
• 'bearer' → 'Bearer <apiKey>'

Returns undefined in proxy mode.

Inherited from

LiveSTTProvider.resolveAuthHeader

resolveBaseUrl()

protected resolveBaseUrl(defaultUrl?): string | undefined;

Defined in: src/providers/base/BaseProvider.ts:307

Resolve the base URL for this provider.

Parameters

Returns

string | undefined

The resolved URL, or undefined when all sources are unset.

Remarks

Priority: proxyUrl > endpoint > defaultUrl.

For WebSocket providers (this.type === 'websocket'), the proxy URL’s http(s) scheme is automatically converted to ws(s).

When no URL is configured and defaultUrl is undefined, the return value is undefined — this lets SDK-based providers (Anthropic, OpenAI) fall back to their own built-in defaults.

Inherited from

LiveSTTProvider.resolveBaseUrl

resolveWsProtocols()

protected resolveWsProtocols(defaultAuthType?): string[] | undefined;

Defined in: src/providers/base/BaseProvider.ts:343

Resolve WebSocket subprotocol for authentication.

Parameters

Returns

string[] | undefined

Subprotocol array for new WebSocket(url, protocols), or undefined.

Remarks

Returns the subprotocol array for direct mode based on authType:

• 'token' → ['token', apiKey] (Deepgram default)
• 'bearer' → ['bearer', apiKey] (OAuth/Bearer tokens)

Returns undefined in proxy mode (no client-side auth needed).

Inherited from

LiveSTTProvider.resolveWsProtocols

sendAudio()

sendAudio(chunk): void;

Defined in: src/providers/base/LiveSTTProvider.ts:128

Send an audio chunk for real-time transcription.

Parameters

Returns

void

Remarks

This is the public method required by the ILiveSTTProvider interface. It delegates to sendAudioToSocket, which subclasses implement to forward audio data over the WebSocket connection. For providers that manage their own audio (e.g. NativeSTT), sendAudioToSocket is a no-op.

Inherited from

LiveSTTProvider.sendAudio

sendAudioToSocket()

protected sendAudioToSocket(chunk): void;

Defined in: src/providers/stt/elevenlabs/ElevenLabsSTT.ts:678

Sends a raw audio chunk to ElevenLabs for real-time transcription.

Parameters

Returns

void

Remarks

The audio ArrayBuffer is base64-encoded and sent as an input_audio_chunk JSON message. The previous_text context field is included only on the first audio chunk (when configured), to provide transcription context without sending it repeatedly.

Overrides

LiveSTTProvider.sendAudioToSocket

sendCommit()

sendCommit(): void;

Defined in: src/providers/stt/elevenlabs/ElevenLabsSTT.ts:739

Manually commits the current audio buffer, finalizing any partial transcript.

Returns

void

Remarks

This method is only meaningful when commitStrategy is 'manual'. In manual mode, the server buffers incoming audio and emits partial_transcript messages but does not finalize (commit) the transcript until instructed. Calling sendCommit() sends an empty input_audio_chunk with commit: true, telling the server to produce a committed_transcript for the buffered audio.

When commitStrategy is 'vad', this method is a no-op because the server automatically commits based on silence detection.

Example

const stt = new ElevenLabsSTT({
  proxyUrl: 'http://localhost:3001/api/proxy/elevenlabs',
  commitStrategy: 'manual',
});

// After streaming audio, manually commit to get final transcript:
stt.sendCommit();

updateConfig()

updateConfig(config): void;

Defined in: src/providers/base/BaseProvider.ts:201

Merge partial configuration updates into the current config.

Parameters

Returns

void

Remarks

After merging, the subclass hook onConfigUpdate is called so providers can react to changed values at runtime.

Inherited from

LiveSTTProvider.updateConfig