> ## 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 TTS > Stream synthesized audio from any SLNG-supported TTS model over the unified WebSocket protocol with init, text, flush, and binary audio frames. ## AsyncAPI ````yaml api-reference/asyncapi/bridges-unmute.asyncapi.yaml /v1/bridges/unmute/tts/{model_variant} id: /v1/bridges/unmute/tts/{model_variant} title: Unmute TTS Bridge description: >- Stream synthesized audio from any SLNG-supported TTS model over the unified WebSocket protocol with init, text, flush, and binary audio frames. 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/tts/{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_1 id: unmuteTtsBridgeReceiveInit title: Unmute tts bridge receive init description: Initialize session on Unmute TTS Bridge type: receive messages: - &ref_11 id: UnmuteTtsInitMessage contentType: application/json payload: - name: Init (Unmute TTS) description: Initialize Unmute TTS session with voice and configuration. type: object properties: - name: type type: string description: init required: true - name: voice type: string description: Voice identifier. required: false - name: config type: object description: Synthesis configuration. required: false properties: - 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: Output audio encoding format. enumValues: - linear16 - mp3 - opus - mulaw - alaw 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: speed type: number description: Speech speed multiplier. required: false headers: [] jsonPayloadSchema: type: object description: Initialize TTS session with voice and configuration. required: - type properties: type: type: string const: init x-parser-schema-id: voice: type: string description: Voice identifier. x-parser-schema-id: config: type: object description: Synthesis configuration. properties: 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: Output audio encoding format. enum: - linear16 - mp3 - opus - mulaw - alaw x-parser-schema-id: language: 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 speed: type: number description: Speech speed multiplier. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Init (Unmute TTS) description: Initialize Unmute TTS session with voice and configuration. example: |- { "type": "init", "voice": "aura-2-thalia-en", "config": { "sample_rate": 24000, "encoding": "linear16" } } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteTtsInitMessage bindings: [] extensions: &ref_0 - id: x-parser-unique-object-id value: /v1/bridges/unmute/tts/{model_variant} - &ref_2 id: unmuteTtsBridgeReceiveText title: Unmute tts bridge receive text description: Send text to Unmute TTS Bridge type: receive messages: - &ref_12 id: UnmuteTtsTextMessage contentType: application/json payload: - name: Text (Unmute TTS) description: Send text to synthesize. type: object properties: - name: type type: string description: text required: true - name: text type: string description: Text to synthesize. required: true - name: flush type: boolean description: Whether to flush immediately after this text. required: false headers: [] jsonPayloadSchema: type: object description: Text to synthesize into audio. required: - type - text properties: type: type: string const: text x-parser-schema-id: text: type: string description: Text to synthesize. x-parser-schema-id: flush: type: boolean description: Whether to flush immediately after this text. x-parser-schema-id: x-parser-schema-id: title: Text (Unmute TTS) description: Send text to synthesize. example: |- { "type": "text", "text": "Hello, how can I help you?" } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteTtsTextMessage bindings: [] extensions: *ref_0 - &ref_3 id: unmuteTtsBridgeReceiveFlush title: Unmute tts bridge receive flush description: Flush buffered output on Unmute TTS Bridge type: receive messages: - &ref_13 id: UnmuteTtsFlushMessage contentType: application/json payload: - name: Flush (Unmute TTS) description: Flush buffered audio. type: object properties: - name: type type: string description: flush required: true headers: [] jsonPayloadSchema: type: object description: Flush any buffered audio to the client. required: - type properties: type: type: string const: flush x-parser-schema-id: x-parser-schema-id: title: Flush (Unmute TTS) description: Flush buffered audio. example: |- { "type": "flush" } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteTtsFlushMessage bindings: [] extensions: *ref_0 - &ref_4 id: unmuteTtsBridgeReceiveClose title: Unmute tts bridge receive close description: Close session on Unmute TTS Bridge type: receive messages: - &ref_14 id: UnmuteTtsCloseMessage contentType: application/json payload: - name: Close (Unmute TTS) description: Close TTS session. type: object properties: - name: type type: string description: close required: true headers: [] jsonPayloadSchema: type: object description: Close the current synthesis session and stop any further audio. required: - type properties: type: type: string const: close x-parser-schema-id: x-parser-schema-id: title: Close (Unmute TTS) description: Close TTS session. example: |- { "type": "close" } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteTtsCloseMessage bindings: [] extensions: *ref_0 - &ref_5 id: unmuteTtsBridgeReceiveKeepalive title: Unmute tts bridge receive keepalive description: Send keepalive on Unmute TTS Bridge type: receive messages: - &ref_15 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_6 id: unmuteTtsBridgeSendReady title: Unmute tts bridge send ready description: Receive ready signal from Unmute TTS Bridge type: send messages: - &ref_16 id: UnmuteTtsReadyMessage contentType: application/json payload: - name: Ready (Unmute TTS) description: Unmute TTS 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 text 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 TTS) description: Unmute TTS 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: UnmuteTtsReadyMessage bindings: [] extensions: *ref_0 - &ref_7 id: unmuteTtsBridgeSendBinaryAudio title: Unmute tts bridge send binary audio description: Receive binary audio frame from Unmute TTS Bridge type: send messages: - &ref_17 id: UnmuteTtsBinaryAudio contentType: application/octet-stream payload: - name: Binary Audio Frame description: Raw binary audio frame from Unmute TTS. type: object properties: - name: type type: string description: >- Placeholder discriminator. The actual message is a raw binary WebSocket frame, not JSON. required: true headers: [] jsonPayloadSchema: type: object description: >- Raw binary audio data sent as a WebSocket binary frame. This is NOT a JSON message — it is a raw audio buffer. The encoding and sample rate match the values specified in the init message config. The object schema below is for documentation purposes only as required by the AsyncAPI tooling. required: - type properties: type: type: string const: binary description: >- Placeholder discriminator. The actual message is a raw binary WebSocket frame, not JSON. x-parser-schema-id: x-parser-schema-id: title: Binary Audio Frame description: Raw binary audio frame from Unmute TTS. example: >- "0000FF00000000FF00000000010101010101010100000000FFFFFFFFFFFEFEFDFEFEFEFEFDFDFEFEFEFEFEFEFEFEFEFFFFFFFFFEFEFEFEFF0001000001020303030303030303030201010000FFFFFEFDFDFDFDFEFFFFFFFF0001020303020201000000FFFDFCFBFAFAFBFAF9F8F7F7F7F6F6F4F2F2F3F7FC000406090F14191A19181715110E0A05FEF9F6F3F0EEECEBEBECEEF2F6F9FC0005090D0F101010100E0C080401" bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteTtsBinaryAudio bindings: [] extensions: *ref_0 - &ref_8 id: unmuteTtsBridgeSendFlushed title: Unmute tts bridge send flushed description: Receive flushed signal from Unmute TTS Bridge type: send messages: - &ref_18 id: UnmuteTtsFlushedMessage contentType: application/json payload: - name: Flushed (Unmute TTS) description: All buffered audio has been flushed. type: object properties: - name: type type: string description: flushed required: true headers: [] jsonPayloadSchema: type: object description: Confirms that all buffered audio has been sent. required: - type properties: type: type: string const: flushed x-parser-schema-id: x-parser-schema-id: title: Flushed (Unmute TTS) description: All buffered audio has been flushed. example: |- { "type": "flushed" } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteTtsFlushedMessage bindings: [] extensions: *ref_0 - &ref_9 id: unmuteTtsBridgeSendAudioEnd title: Unmute tts bridge send audio end description: Receive audio end from Unmute TTS Bridge type: send messages: - &ref_19 id: UnmuteTtsAudioEndMessage contentType: application/json payload: - name: Audio End (Unmute TTS) description: All audio for the current synthesis has been sent. type: object properties: - name: type type: string description: audio_end required: true - name: data type: object description: Audio-end event envelope. required: true properties: - name: event_type type: string description: Audio-end event kind. required: true headers: [] jsonPayloadSchema: type: object description: Indicates all audio has been sent for the current synthesis. required: - type - data properties: type: type: string const: audio_end x-parser-schema-id: data: type: object description: Audio-end event envelope. required: - event_type properties: event_type: type: string description: Audio-end event kind. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Audio End (Unmute TTS) description: All audio for the current synthesis has been sent. example: |- { "type": "audio_end", "data": { "event_type": "final" } } bindings: [] extensions: - id: x-parser-unique-object-id value: UnmuteTtsAudioEndMessage bindings: [] extensions: *ref_0 - &ref_10 id: unmuteTtsBridgeSendError title: Unmute tts bridge send error description: Receive error from Unmute TTS Bridge type: send messages: - &ref_20 id: UnmuteTtsErrorMessage contentType: application/json payload: - name: Error (Unmute TTS) description: Error occurred during Unmute TTS 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 synthesis. 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 TTS) description: Error occurred during Unmute TTS 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: UnmuteTtsErrorMessage bindings: [] extensions: *ref_0 sendOperations: - *ref_1 - *ref_2 - *ref_3 - *ref_4 - *ref_5 receiveOperations: - *ref_6 - *ref_7 - *ref_8 - *ref_9 - *ref_10 sendMessages: - *ref_11 - *ref_12 - *ref_13 - *ref_14 - *ref_15 receiveMessages: - *ref_16 - *ref_17 - *ref_18 - *ref_19 - *ref_20 extensions: - id: x-parser-unique-object-id value: /v1/bridges/unmute/tts/{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: [] ````