> ## 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. # Speech AI Real-time v5 > Stream real-time transcripts from Soniox Speech AI v5 over WebSocket with speaker diarization, language detection, and configurable endpoint detection. **Hosting: routed through SLNG (Soniox).** This model runs on Soniox's servers; SLNG proxies each request through the nearest regional gateway. Available in Netherlands, Germany, United States (East, West), Australia, Brazil, United Kingdom, Indonesia, Israel, India, Japan, Singapore, South Africa. Connect to your region's gateway WebSocket endpoint: `wss://eu-north.api.slng.ai`, `wss://eu-west.api.slng.ai`, `wss://us-east.api.slng.ai`, `wss://us-west.api.slng.ai`, `wss://au.api.slng.ai`, `wss://br.api.slng.ai`, `wss://gb.api.slng.ai`, `wss://id.api.slng.ai`, `wss://il.api.slng.ai`, `wss://in.api.slng.ai`, `wss://jp.api.slng.ai`, `wss://sg.api.slng.ai`, `wss://za.api.slng.ai`. ## AsyncAPI ````yaml api-reference/asyncapi/stt-soniox.asyncapi.yaml /v1/stt/soniox/speech-ai:rt-v5 id: /v1/stt/soniox/speech-ai:rt-v5 title: Speech AI Real-time v5 description: >- Stream real-time transcripts from Soniox Speech AI v5 over WebSocket with speaker diarization, language detection, and configurable endpoint detection. servers: - id: production-eu-north protocol: wss host: eu-north.api.slng.ai bindings: [] variables: [] - id: production-eu-west protocol: wss host: eu-west.api.slng.ai bindings: [] variables: [] - id: production-us-east protocol: wss host: us-east.api.slng.ai bindings: [] variables: [] - id: production-us-west protocol: wss host: us-west.api.slng.ai bindings: [] variables: [] - id: production-au protocol: wss host: au.api.slng.ai bindings: [] variables: [] - id: production-br protocol: wss host: br.api.slng.ai bindings: [] variables: [] - id: production-gb protocol: wss host: gb.api.slng.ai bindings: [] variables: [] - id: production-id protocol: wss host: id.api.slng.ai bindings: [] variables: [] - id: production-il protocol: wss host: il.api.slng.ai bindings: [] variables: [] - id: production-in protocol: wss host: in.api.slng.ai bindings: [] variables: [] - id: production-jp protocol: wss host: jp.api.slng.ai bindings: [] variables: [] - id: production-sg protocol: wss host: sg.api.slng.ai bindings: [] variables: [] - id: production-za protocol: wss host: za.api.slng.ai bindings: [] variables: [] address: /v1/stt/soniox/speech-ai:rt-v5 parameters: [] bindings: - protocol: ws version: latest value: method: GET schemaProperties: - name: method type: string description: GET required: false operations: - &ref_1 id: sttSonioxSpeechAiRtV5ReceiveInit title: Stt soniox speech ai rt v5 receive init description: Initialize session on Speech AI Real-time v5 type: receive messages: - &ref_8 id: SonioxSttInitRequest contentType: application/json payload: - name: Init Request (Soniox) description: >- Initialize a Soniox STT session with provider-specific recognition configuration. type: object properties: - name: type type: string description: config required: true - name: model type: string description: Real-time model to use. required: false - name: audio_format type: string description: >- Audio format of the stream. Use `auto` to let Soniox detect container formats. enumValues: - pcm_s16le - pcm_f32le - wav - ogg - flac - auto required: false - name: sample_rate type: integer description: Audio sample rate in Hz (required for raw PCM formats). required: false - name: num_channels type: integer description: Number of audio channels (required for raw PCM formats). required: false - name: enable_speaker_diarization type: boolean description: Enable speaker identification and separation. required: false - name: enable_language_identification type: boolean description: Automatically detect spoken language. required: false - name: enable_endpoint_detection type: boolean description: Enable endpoint detection for utterance boundaries. required: false - name: max_endpoint_delay_ms type: integer description: >- Max endpoint detection delay in milliseconds (500–3000). Soniox's native default is 2000ms; this endpoint defaults to 500ms for lower latency. required: false - name: language_hints type: array description: Language hints for transcription. required: false properties: - name: item type: string required: false - name: language_hints_strict type: boolean description: Only transcribe in specified languages. required: false - name: context type: object description: Context information for improved accuracy. required: false properties: - name: general type: array required: false properties: - name: key type: string required: false - name: value type: string required: false - name: text type: string required: false - name: terms type: array required: false properties: - name: item type: string required: false - name: translation type: object description: Translation configuration. required: false properties: - name: type type: string enumValues: - one_way - two_way required: false - name: target_language type: string required: false - name: language_a type: string required: false - name: language_b type: string required: false - name: client_reference_id type: string description: Client reference ID for tracking. required: false headers: [] jsonPayloadSchema: type: object description: >- Initialize a Soniox Speech AI STT session with provider-specific configuration options before streaming audio. All configuration fields are sent at the root of the message alongside `type` (not nested under a `config` key); the gateway translates this SLNG-side `config` message into Soniox's native init payload before forwarding, and only the fields listed below are forwarded — unknown fields are dropped. Soniox's `api_key` is injected by the gateway from the `Authorization: Bearer ` header, so do not send it. Full field semantics: https://soniox.com/docs/stt/api-reference/websocket-api required: - type properties: type: type: string const: config x-parser-schema-id: model: type: string description: Real-time model to use. default: stt-rt-v5 x-parser-schema-id: audio_format: type: string description: >- Audio format of the stream. Use `auto` to let Soniox detect container formats. default: pcm_s16le enum: - pcm_s16le - pcm_f32le - wav - ogg - flac - auto x-parser-schema-id: sample_rate: type: integer description: Audio sample rate in Hz (required for raw PCM formats). default: 16000 x-parser-schema-id: num_channels: type: integer description: Number of audio channels (required for raw PCM formats). default: 1 x-parser-schema-id: enable_speaker_diarization: type: boolean description: Enable speaker identification and separation. x-parser-schema-id: enable_language_identification: type: boolean description: Automatically detect spoken language. x-parser-schema-id: enable_endpoint_detection: type: boolean description: Enable endpoint detection for utterance boundaries. default: true x-parser-schema-id: max_endpoint_delay_ms: type: integer description: >- Max endpoint detection delay in milliseconds (500–3000). Soniox's native default is 2000ms; this endpoint defaults to 500ms for lower latency. minimum: 500 maximum: 3000 default: 500 x-parser-schema-id: language_hints: type: array description: Language hints for transcription. items: type: string x-parser-schema-id: x-parser-schema-id: language_hints_strict: type: boolean description: Only transcribe in specified languages. x-parser-schema-id: context: type: object description: Context information for improved accuracy. properties: general: type: array items: type: object properties: key: type: string x-parser-schema-id: value: type: string x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: text: type: string x-parser-schema-id: terms: type: array items: type: string x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: translation: type: object description: Translation configuration. properties: type: type: string enum: - one_way - two_way x-parser-schema-id: target_language: type: string x-parser-schema-id: language_a: type: string x-parser-schema-id: language_b: type: string x-parser-schema-id: x-parser-schema-id: client_reference_id: type: string maxLength: 256 description: Client reference ID for tracking. x-parser-schema-id: x-parser-schema-id: title: Init Request (Soniox) description: >- Initialize a Soniox STT session with provider-specific recognition configuration. example: |- { "type": "config", "model": "stt-rt-v5", "audio_format": "pcm_s16le", "sample_rate": 16000, "num_channels": 1, "enable_speaker_diarization": true, "enable_endpoint_detection": true, "max_endpoint_delay_ms": 500, "language_hints": [ "en" ] } bindings: [] extensions: - id: x-parser-unique-object-id value: SonioxSttInitRequest bindings: [] extensions: &ref_0 - id: x-parser-unique-object-id value: /v1/stt/soniox/speech-ai:rt-v5 - &ref_2 id: sttSonioxSpeechAiRtV5ReceiveAudio title: Stt soniox speech ai rt v5 receive audio description: Send audio frame to Speech AI Real-time v5 type: receive messages: - &ref_9 id: SonioxSttBinaryAudio contentType: application/octet-stream payload: - type: string format: binary description: >- Stream raw binary audio frames to be transcribed. Sent as binary WebSocket frames (NOT JSON) — no envelope, no base64 encoding. Frame format must match the `audio_format`, `sample_rate`, and `num_channels` declared in the init message (default `pcm_s16le` at 16kHz mono). x-parser-schema-id: name: Binary Audio Frame headers: [] jsonPayloadSchema: type: string format: binary description: >- Raw binary audio data matching the declared `audio_format`. Sent as a binary WebSocket frame — no JSON envelope, no base64 encoding. x-parser-schema-id: title: Binary Audio Frame description: >- Stream raw binary audio frames to be transcribed. Sent as binary WebSocket frames (NOT JSON) — no envelope, no base64 encoding. Frame format must match the `audio_format`, `sample_rate`, and `num_channels` declared in the init message (default `pcm_s16le` at 16kHz mono). example: >- "0000FF00000000FF00000000010101010101010100000000FFFFFFFFFFFFFEFEFDFEFEFEFEFDFDFEFEFEFEFEFEFEFEFEFFFFFFFFFEFEFEFEFF000100001020303030303030303030201010000FFFFFEFDFDFDFDFEFFFFFFFF0001020303020201000000FFFDFCFBFAFAFBFAF9F8F7F7F7F6F6F4F2F2F3F7FC000406090F14191A19181715110E0A05FEF9F6F3F0EEECEBEBECEEF2F6F9FC0005090D0F101010100E0C080401" bindings: [] extensions: - id: x-parser-unique-object-id value: SonioxSttBinaryAudio bindings: [] extensions: *ref_0 - &ref_3 id: sttSonioxSpeechAiRtV5ReceiveFinalize title: Stt soniox speech ai rt v5 receive finalize description: Force-finalize buffered audio on Speech AI Real-time v5 type: receive messages: - &ref_10 id: SttFinalizeMessage contentType: application/json payload: - name: Finalize Message description: >- Force-finalize buffered audio tokens without closing the connection. type: object properties: - name: type type: string description: finalize required: true headers: [] jsonPayloadSchema: type: object description: >- Mid-stream flush — forces Soniox to finalize any buffered audio and return results. The connection remains open for further audio. Server responds with finalized tokens terminated by a `` marker. required: - type properties: type: type: string const: finalize x-parser-schema-id: x-parser-schema-id: title: Finalize Message description: Force-finalize buffered audio tokens without closing the connection. example: |- { "type": "finalize" } bindings: [] extensions: - id: x-parser-unique-object-id value: SttFinalizeMessage bindings: [] extensions: *ref_0 - &ref_4 id: sttSonioxSpeechAiRtV5ReceiveKeepalive title: Stt soniox speech ai rt v5 receive keepalive description: Send keepalive on Speech AI Real-time v5 type: receive messages: - &ref_11 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 at least every 20 seconds when not streaming audio 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_5 id: sttSonioxSpeechAiRtV5ReceiveClose title: Stt soniox speech ai rt v5 receive close description: Close audio stream on Speech AI Real-time v5 type: receive messages: - &ref_12 id: SttCloseMessage contentType: application/json payload: - name: Close Message description: Signal end of audio stream. type: object properties: - name: type type: string description: Empty string. Gateway maps this to an empty binary frame. required: true headers: [] jsonPayloadSchema: type: object description: >- Signal end-of-stream. The gateway translates `{"type": ""}` into an empty binary WebSocket frame forwarded to Soniox — Soniox's native end-of-stream signal per its docs. Alternatively, simply close the WebSocket directly from the client. required: - type properties: type: type: string const: '' description: Empty string. Gateway maps this to an empty binary frame. x-parser-schema-id: x-parser-schema-id: title: Close Message description: Signal end of audio stream. example: |- { "type": "" } bindings: [] extensions: - id: x-parser-unique-object-id value: SttCloseMessage bindings: [] extensions: *ref_0 - &ref_6 id: sttSonioxSpeechAiRtV5SendTokensFrame title: Stt soniox speech ai rt v5 send tokens frame description: Receive native Soniox tokens frame from Speech AI Real-time v5 type: send messages: - &ref_13 id: SonioxSttTokensFrame contentType: application/json payload: - name: Tokens Frame (Soniox native) description: >- Native Soniox tokens frame forwarded unchanged from the upstream provider. type: object properties: - name: tokens type: array description: >- Transcription tokens with per-token timing, confidence, speaker and language. Tokens are sub-word chunks (e.g. `" co"`, `"uld"`) rather than whole words — concatenate `text` across tokens to reconstruct the transcript. Empty on the initial warmup frame. required: true properties: - name: text type: string description: >- Token text. Endpoint markers `` / `` may appear here when endpoint detection is enabled. required: false - name: start_ms type: number description: Token start time in milliseconds. required: false - name: end_ms type: number description: Token end time in milliseconds. required: false - name: confidence type: number description: Token confidence score. required: false - name: is_final type: boolean description: Whether this token is finalized. required: false - name: speaker type: string description: Speaker identifier (when diarization is enabled). required: false - name: language type: string description: >- ISO 639-1 two-letter language code for this token (when language identification or translation is enabled). required: false - name: translation_status type: string description: >- Translation state of the token. `none` when translation is disabled or the token is not to be translated; `original` for source-language tokens; `translation` for translated tokens (accompanied by `source_language`). enumValues: - none - original - translation required: false - name: source_language type: string description: >- ISO 639-1 code of the source language. Only present on tokens with `translation_status: translation`. required: false - name: final_audio_proc_ms type: number description: >- Cumulative audio processing time for finalized tokens, in milliseconds. required: false - name: total_audio_proc_ms type: number description: Total audio processing time for the session, in milliseconds. required: false headers: [] jsonPayloadSchema: type: object description: >- Native Soniox Speech AI server frame forwarded unchanged, discriminated by presence of the `tokens` array. Three variants share this shape: a warmup heartbeat emitted right after session init before any audio is transcribed (empty `tokens`, both processing timers `0`); interim frames with `is_final: false`; and final frames with `is_final: true`, optionally terminated by an `` or `` endpoint marker token when `enable_endpoint_detection` is enabled. required: - tokens properties: tokens: type: array description: >- Transcription tokens with per-token timing, confidence, speaker and language. Tokens are sub-word chunks (e.g. `" co"`, `"uld"`) rather than whole words — concatenate `text` across tokens to reconstruct the transcript. Empty on the initial warmup frame. items: type: object properties: text: type: string description: >- Token text. Endpoint markers `` / `` may appear here when endpoint detection is enabled. x-parser-schema-id: start_ms: type: number description: Token start time in milliseconds. x-parser-schema-id: end_ms: type: number description: Token end time in milliseconds. x-parser-schema-id: confidence: type: number description: Token confidence score. x-parser-schema-id: is_final: type: boolean description: Whether this token is finalized. x-parser-schema-id: speaker: type: string description: Speaker identifier (when diarization is enabled). x-parser-schema-id: language: type: string description: >- ISO 639-1 two-letter language code for this token (when language identification or translation is enabled). x-parser-schema-id: translation_status: type: string enum: - none - original - translation description: >- Translation state of the token. `none` when translation is disabled or the token is not to be translated; `original` for source-language tokens; `translation` for translated tokens (accompanied by `source_language`). x-parser-schema-id: source_language: type: string description: >- ISO 639-1 code of the source language. Only present on tokens with `translation_status: translation`. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: final_audio_proc_ms: type: number description: >- Cumulative audio processing time for finalized tokens, in milliseconds. x-parser-schema-id: total_audio_proc_ms: type: number description: Total audio processing time for the session, in milliseconds. x-parser-schema-id: x-parser-schema-id: title: Tokens Frame (Soniox native) description: >- Native Soniox tokens frame forwarded unchanged from the upstream provider. example: |- { "tokens": [], "final_audio_proc_ms": 0, "total_audio_proc_ms": 0 } bindings: [] extensions: - id: x-parser-unique-object-id value: SonioxSttTokensFrame bindings: [] extensions: *ref_0 - &ref_7 id: sttSonioxSpeechAiRtV5SendErrorFrame title: Stt soniox speech ai rt v5 send error frame description: Receive native Soniox error frame from Speech AI Real-time v5 type: send messages: - &ref_14 id: SonioxSttErrorFrame contentType: application/json payload: - name: Error Frame (Soniox native) description: >- Native Soniox error frame forwarded unchanged from the upstream provider. type: object properties: - name: error_code type: integer description: Soniox numeric error code. required: true - name: error_message type: string description: Human-readable error description from Soniox. required: true headers: [] jsonPayloadSchema: type: object description: >- Native Soniox error frame. Discriminated by presence of `error_code`. required: - error_code - error_message properties: error_code: type: integer description: Soniox numeric error code. x-parser-schema-id: error_message: type: string description: Human-readable error description from Soniox. x-parser-schema-id: x-parser-schema-id: title: Error Frame (Soniox native) description: >- Native Soniox error frame forwarded unchanged from the upstream provider. example: |- { "error_code": 401, "error_message": "Invalid or expired API key" } bindings: [] extensions: - id: x-parser-unique-object-id value: SonioxSttErrorFrame bindings: [] extensions: *ref_0 sendOperations: - *ref_1 - *ref_2 - *ref_3 - *ref_4 - *ref_5 receiveOperations: - *ref_6 - *ref_7 sendMessages: - *ref_8 - *ref_9 - *ref_10 - *ref_11 - *ref_12 receiveMessages: - *ref_13 - *ref_14 extensions: - id: x-parser-unique-object-id value: /v1/stt/soniox/speech-ai:rt-v5 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: [] ````