> ## Documentation Index > Fetch the complete documentation index at: https://docs.slng.ai/llms.txt > Use this file to discover all available pages before exploring further. # Unified STT > Stream audio to any SLNG-supported STT model over the unified WebSocket protocol with init, audio, finalize, partial, and final transcript messages. ## AsyncAPI ````yaml api-reference/asyncapi/bridges-unmute.asyncapi.yaml /v1/bridges/unmute/stt/{model_variant} id: /v1/bridges/unmute/stt/{model_variant} title: Unmute STT Bridge description: >- Stream audio to any SLNG-supported STT model over the unified WebSocket protocol with init, audio, finalize, partial, and final transcript messages. servers: - id: production protocol: wss host: api.slng.ai bindings: [] variables: [] - id: staging protocol: wss host: stageapi.slng.ai bindings: [] variables: [] address: /v1/bridges/unmute/stt/{model_variant} parameters: [] bindings: - protocol: ws version: latest value: method: GET headers: type: object properties: X-Region-Override: type: string description: Target region override. Auto-selected if not provided. x-parser-schema-id: X-World-Part-Override: type: string description: Target world part override. Auto-selected if not provided. x-parser-schema-id: x-parser-schema-id: WebsocketHeaders query: type: object properties: region: type: string description: >- Target region override as a query parameter. Auto-selected if not provided. Equivalent to the `X-Region-Override` header; the header takes precedence when both are set. enum: - ap-southeast-2 - eu-north-1 - us-east-1 x-parser-schema-id: world-part: type: string description: >- Target world part override as a query parameter. Auto-selected if not provided. Equivalent to the `X-World-Part-Override` header; the header takes precedence when both are set. enum: - ap - eu - na x-parser-schema-id: x-parser-schema-id: WebsocketQueryParams schemaProperties: - name: method type: string description: GET required: false - name: headers type: object required: false properties: - name: X-Region-Override type: string description: Target region override. Auto-selected if not provided. required: false - name: X-World-Part-Override type: string description: Target world part override. Auto-selected if not provided. required: false - name: query type: object required: false properties: - name: region type: string description: >- Target region override as a query parameter. Auto-selected if not provided. Equivalent to the `X-Region-Override` header; the header takes precedence when both are set. enumValues: - ap-southeast-2 - eu-north-1 - us-east-1 required: false - name: world-part type: string description: >- Target world part override as a query parameter. Auto-selected if not provided. Equivalent to the `X-World-Part-Override` header; the header takes precedence when both are set. enumValues: - ap - eu - na required: false operations: - &ref_2 id: unmuteSttBridgeReceiveInit title: Unmute stt bridge receive init description: Initialize session on Unmute STT Bridge type: receive messages: - &ref_12 id: UnmuteSttInitMessage contentType: application/json payload: - name: Init (Unmute STT) description: Initialize Unmute STT session with configuration. type: object properties: - name: type type: string description: init required: true - name: config type: object description: Session configuration. required: false properties: - name: language type: string description: ISO-639-1 language code. enumValues: - en - ja - zh - de - hi - fr - ko - pt - it - es - id - nl - tr - fil - pl - sv - bg - ro - ar - cs - el - fi - hr - ms - sk - da - ta - uk - ru - hu - 'no' - vi required: false - name: sample_rate type: integer description: Audio sample rate in Hz. enumValues: - 8000 - 16000 - 22050 - 24000 - 32000 - 44100 - 48000 required: false - name: encoding type: string description: Audio encoding format. enumValues: - linear16 - mp3 - opus required: false - name: enable_vad type: boolean description: Enable voice activity detection. required: false - name: enable_partials type: boolean description: Enable partial transcription results. required: false headers: [] jsonPayloadSchema: type: object description: Initialize STT session with optional configuration. required: - type properties: type: type: string const: init x-parser-schema-id: config: type: object description: Session configuration. properties: language: &ref_1 type: string description: ISO-639-1 language code. enum: - en - ja - zh - de - hi - fr - ko - pt - it - es - id - nl - tr - fil - pl - sv - bg - ro - ar - cs - el - fi - hr - ms - sk - da - ta - uk - ru - hu - 'no' - vi x-parser-schema-id: LanguageCode sample_rate: type: integer description: Audio sample rate in Hz. enum: - 8000 - 16000 - 22050 - 24000 - 32000 - 44100 - 48000 x-parser-schema-id: SampleRate encoding: type: string description: Audio encoding format. enum: - linear16 - mp3 - opus x-parser-schema-id: enable_vad: type: boolean description: Enable voice activity detection. x-parser-schema-id: enable_partials: type: boolean description: Enable partial transcription results. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Init (Unmute STT) description: Initialize Unmute STT session with configuration. example: |- { "type": "init", "config": { "language": "en", "sample_rate": 16000, "encoding": "linear16", "enable_partials": true } } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteSttInitMessage bindings: [] extensions: &ref_0 - id: x-parser-unique-object-id value: /v1/bridges/unmute/stt/{model_variant} - &ref_3 id: unmuteSttBridgeReceiveAudio title: Unmute stt bridge receive audio description: Send audio to Unmute STT Bridge type: receive messages: - &ref_13 id: UnmuteSttAudioMessage contentType: application/json payload: - name: Audio (Unmute STT) description: Send audio data to Unmute STT Bridge. type: object properties: - name: type type: string description: audio required: true - name: data type: string description: Base64-encoded audio data. required: true headers: [] jsonPayloadSchema: type: object description: Audio data for transcription. required: - type - data properties: type: type: string const: audio x-parser-schema-id: data: type: string format: byte description: Base64-encoded audio data. x-parser-schema-id: x-parser-schema-id: title: Audio (Unmute STT) description: Send audio data to Unmute STT Bridge. example: |- { "type": "audio", "data": "UklGRiQAAABXQVZFZm10IBAAAAABAAEA..." } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteSttAudioMessage bindings: [] extensions: *ref_0 - &ref_4 id: unmuteSttBridgeReceiveFinalize title: Unmute stt bridge receive finalize description: Force-finalize buffered audio on Unmute STT Bridge type: receive messages: - &ref_14 id: UnmuteSttFinalizeMessage contentType: application/json payload: - name: Finalize (Unmute STT) description: Force-finalize buffered audio without closing the connection. type: object properties: - name: type type: string description: finalize required: true headers: [] jsonPayloadSchema: type: object description: >- Mid-stream flush — forces the server to finalize any buffered audio and return results. The connection remains open for further audio. required: - type properties: type: type: string const: finalize x-parser-schema-id: x-parser-schema-id: title: Finalize (Unmute STT) description: Force-finalize buffered audio without closing the connection. example: |- { "type": "finalize" } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteSttFinalizeMessage bindings: [] extensions: *ref_0 - &ref_5 id: unmuteSttBridgeReceiveClose title: Unmute stt bridge receive close description: Close audio stream on Unmute STT Bridge type: receive messages: - &ref_15 id: UnmuteSttCloseMessage contentType: application/json payload: - name: Close (Unmute STT) description: Signal end of audio stream and close the connection. type: object properties: - name: type type: string description: close required: true headers: [] jsonPayloadSchema: type: object description: >- Signal that no more audio will be sent. The server processes remaining audio, sends final results, then closes the connection. required: - type properties: type: type: string const: close x-parser-schema-id: x-parser-schema-id: title: Close (Unmute STT) description: Signal end of audio stream and close the connection. example: |- { "type": "close" } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteSttCloseMessage bindings: [] extensions: *ref_0 - &ref_6 id: unmuteSttBridgeReceiveKeepalive title: Unmute stt bridge receive keepalive description: Send keepalive on Unmute STT Bridge type: receive messages: - &ref_16 id: KeepaliveMessage contentType: application/json payload: - name: Keepalive Message description: Keep the WebSocket connection alive during silence. type: object properties: - name: type type: string description: keepalive required: true headers: [] jsonPayloadSchema: type: object description: >- Prevents the connection from being closed due to inactivity. Send periodically during silence to maintain the session. required: - type properties: type: type: string const: keepalive x-parser-schema-id: x-parser-schema-id: title: Keepalive Message description: Keep the WebSocket connection alive during silence. example: |- { "type": "keepalive" } bindings: [] extensions: - id: x-parser-unique-object-id value: KeepaliveMessage bindings: [] extensions: *ref_0 - &ref_7 id: unmuteSttBridgeSendReady title: Unmute stt bridge send ready description: Receive ready signal from Unmute STT Bridge type: send messages: - &ref_17 id: UnmuteSttReadyMessage contentType: application/json payload: - name: Ready (Unmute STT) description: Unmute STT session is ready. type: object properties: - name: type type: string description: ready required: true - name: session_id type: string description: Unique session identifier. required: true - name: slng_request_id type: string description: SLNG request identifier echoed back for log correlation. required: true headers: [] jsonPayloadSchema: type: object description: Session is ready for audio input. required: - type - session_id - slng_request_id properties: type: type: string const: ready x-parser-schema-id: session_id: type: string description: Unique session identifier. x-parser-schema-id: slng_request_id: type: string description: SLNG request identifier echoed back for log correlation. x-parser-schema-id: x-parser-schema-id: title: Ready (Unmute STT) description: Unmute STT session is ready. example: |- { "type": "ready", "session_id": "1e1a9598-077e-4d9d-aba6-78af6363f27c", "slng_request_id": "2c9953d7-d4b4-4385-bb27-f64e0d979be5" } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteSttReadyMessage bindings: [] extensions: *ref_0 - &ref_8 id: unmuteSttBridgeSendPartialTranscript title: Unmute stt bridge send partial transcript description: Receive partial transcript from Unmute STT Bridge type: send messages: - &ref_18 id: UnmuteSttPartialTranscript contentType: application/json payload: - name: Partial Transcript (Unmute STT) description: Partial (interim) transcription result. type: object properties: - name: type type: string description: partial_transcript required: true - name: transcript type: string description: Transcribed text so far. required: true - name: confidence type: number description: Confidence score (0-1). required: false headers: [] jsonPayloadSchema: type: object description: Interim transcription result. required: - type - transcript properties: type: type: string const: partial_transcript x-parser-schema-id: transcript: type: string description: Transcribed text so far. x-parser-schema-id: confidence: type: number description: Confidence score (0-1). x-parser-schema-id: x-parser-schema-id: title: Partial Transcript (Unmute STT) description: Partial (interim) transcription result. example: |- { "type": "partial_transcript", "transcript": "Hello wor", "confidence": 0.85 } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteSttPartialTranscript bindings: [] extensions: *ref_0 - &ref_9 id: unmuteSttBridgeSendFinalTranscript title: Unmute stt bridge send final transcript description: Receive final transcript from Unmute STT Bridge type: send messages: - &ref_19 id: UnmuteSttFinalTranscript contentType: application/json payload: - name: Final Transcript (Unmute STT) description: Final transcription result. type: object properties: - name: type type: string description: final_transcript required: true - name: transcript type: string description: Final transcribed text. required: true - name: confidence type: number description: Confidence score (0-1). required: false - name: language type: string description: ISO-639-1 language code. enumValues: - en - ja - zh - de - hi - fr - ko - pt - it - es - id - nl - tr - fil - pl - sv - bg - ro - ar - cs - el - fi - hr - ms - sk - da - ta - uk - ru - hu - 'no' - vi required: false - name: duration type: number description: Audio duration in seconds. required: false headers: [] jsonPayloadSchema: type: object description: Final transcription result for an utterance. required: - type - transcript properties: type: type: string const: final_transcript x-parser-schema-id: transcript: type: string description: Final transcribed text. x-parser-schema-id: confidence: type: number description: Confidence score (0-1). x-parser-schema-id: language: *ref_1 duration: type: number description: Audio duration in seconds. x-parser-schema-id: x-parser-schema-id: title: Final Transcript (Unmute STT) description: Final transcription result. example: |- { "type": "final_transcript", "transcript": "Hello world", "confidence": 0.95, "language": "en", "duration": 2.5 } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteSttFinalTranscript bindings: [] extensions: *ref_0 - &ref_10 id: unmuteSttBridgeSendUtteranceEnd title: Unmute stt bridge send utterance end description: Receive utterance end marker from Unmute STT Bridge type: send messages: - &ref_20 id: UnmuteSttUtteranceEnd contentType: application/json payload: - name: Utterance End (Unmute STT) description: Endpoint marker indicating the end of a spoken utterance. type: object properties: - name: type type: string description: utterance_end required: true - name: last_word_end type: number description: >- End time of the last finalized word in seconds, when available. required: false headers: [] jsonPayloadSchema: type: object description: | Signals the end of an utterance. Emitted by the bridge when the upstream provider returns a final endpoint marker (e.g., Soniox `` / `` tokens). Requires the model's catalog to declare a `tokenStream` with `finalMarkers`, and endpoint detection to be enabled in the session config. required: - type properties: type: type: string const: utterance_end x-parser-schema-id: last_word_end: type: number description: End time of the last finalized word in seconds, when available. x-parser-schema-id: x-parser-schema-id: title: Utterance End (Unmute STT) description: Endpoint marker indicating the end of a spoken utterance. example: |- { "type": "utterance_end", "last_word_end": 2.48 } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteSttUtteranceEnd bindings: [] extensions: *ref_0 - &ref_11 id: unmuteSttBridgeSendError title: Unmute stt bridge send error description: Receive error from Unmute STT Bridge type: send messages: - &ref_21 id: UnmuteSttErrorMessage contentType: application/json payload: - name: Error (Unmute STT) description: Error occurred during Unmute STT session. type: object properties: - name: type type: string description: error required: true - name: data type: object description: Structured error envelope. required: true properties: - name: request_id type: string description: SLNG request identifier for this error. required: true - name: message type: string description: Human-readable error description. required: true - name: code type: string description: Error code. enumValues: - auth_error - config_error - rate_limit - provider_error required: true - name: message type: string description: >- Human-readable error description (duplicated from `data.message` for backward compatibility). required: true - name: code type: string description: >- Error code (duplicated from `data.code` for backward compatibility). enumValues: - auth_error - config_error - rate_limit - provider_error required: true headers: [] jsonPayloadSchema: type: object description: >- Error occurred during transcription. The error details live under `data`; `message` and `code` are duplicated at the top level for backward compatibility. required: - type - data - message - code properties: type: type: string const: error x-parser-schema-id: data: type: object description: Structured error envelope. required: - request_id - message - code properties: request_id: type: string description: SLNG request identifier for this error. x-parser-schema-id: message: type: string description: Human-readable error description. x-parser-schema-id: code: type: string description: Error code. enum: - auth_error - config_error - rate_limit - provider_error x-parser-schema-id: x-parser-schema-id: message: type: string description: >- Human-readable error description (duplicated from `data.message` for backward compatibility). x-parser-schema-id: code: type: string description: >- Error code (duplicated from `data.code` for backward compatibility). enum: - auth_error - config_error - rate_limit - provider_error x-parser-schema-id: x-parser-schema-id: title: Error (Unmute STT) description: Error occurred during Unmute STT session. example: |- { "type": "error", "data": { "request_id": "req_abc123", "message": "Upstream service unavailable", "code": "provider_error" }, "message": "Upstream service unavailable", "code": "provider_error" } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteSttErrorMessage bindings: [] extensions: *ref_0 sendOperations: - *ref_2 - *ref_3 - *ref_4 - *ref_5 - *ref_6 receiveOperations: - *ref_7 - *ref_8 - *ref_9 - *ref_10 - *ref_11 sendMessages: - *ref_12 - *ref_13 - *ref_14 - *ref_15 - *ref_16 receiveMessages: - *ref_17 - *ref_18 - *ref_19 - *ref_20 - *ref_21 extensions: - id: x-parser-unique-object-id value: /v1/bridges/unmute/stt/{model_variant} securitySchemes: - id: bearer name: bearer type: http description: > API key issued by SLNG. Pass as `Authorization: Bearer ` in the WebSocket upgrade request headers. scheme: bearer extensions: [] ````