> ## Documentation Index > Fetch the complete documentation index at: https://developers.meshapi.ai/llms.txt > Use this file to discover all available pages before exploring further. # Text to Speech > Text-to-speech, speech-to-text, voice management, and real-time streaming audio APIs. # Audio Generation Mesh API provides a full suite of audio endpoints — convert text to speech, transcribe audio files, stream TTS/STT in real time, and browse available voices — all through a single API key. All endpoints share the same base URL: `https://api.meshapi.ai/v1/audio` **Auth:** `Authorization: Bearer rsk_` on all REST requests. WebSocket endpoints accept the key via `Sec-WebSocket-Protocol: Bearer ` or `?api_key=`. *** ## Text-to-Speech `POST /v1/audio/speech` Convert a text string into audio. The brand behind a model (ElevenLabs, Sarvam, etc.) is selected automatically based on the model you pass — models like `hexgrad/kokoro-82m` and `cartesia/sonic-2` are also available. Streaming is enabled by default. ### Request body | Field | Type | Default | Description | | :--------------------------- | :------ | :------------------ | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `model` | string | `eleven_flash_v2_5` | Model ID. Determines which provider handles the request. | | `input` | string | — | Text to synthesize. **Required.** | | `voice` | string | — | Voice ID/name for the selected model's brand (an ElevenLabs voice ID, or a Kokoro/Cartesia voice). Browse valid IDs with `GET /v1/audio/voices` (filter by `brand`, `model`, or `search`). Required for ElevenLabs models. | | `speaker` | string | `anushka` | Speaker name for Sarvam models. Ignored for ElevenLabs. | | `stream` | boolean | `true` | Stream audio chunks as they are generated. | | `response_format` | string | provider default | Output audio format (e.g. `mp3_44100_128`, `pcm_22050`, `wav_44100`). | | `language_code` | string | — | BCP-47 language code (e.g. `en-US`). | | `voice_settings` | object | — | Fine-tune ElevenLabs voice: `stability`, `similarity_boost`, `style`, `use_speaker_boost`, `speed`. | | `seed` | integer | — | Reproducible generation seed. | | `previous_text` | string | — | Text that came before `input` — used for better prosody. | | `next_text` | string | — | Text that comes after `input` — used for better prosody. | | `apply_text_normalization` | string | — | `auto`, `on`, or `off`. Controls ElevenLabs text normalizer. | | `enable_logging` | boolean | — | Pass `false` to opt out of ElevenLabs request logging. | | `optimize_streaming_latency` | integer | — | ElevenLabs latency-quality trade-off level (0–4). | | `pitch` | float | — | Sarvam pitch adjustment. | | `pace` | float | — | Sarvam speaking pace. | | `loudness` | float | — | Sarvam output loudness. | | `target_language_code` | string | `hi-IN` | Sarvam target language. | ### Supported output formats **Streaming (`stream: true`):** `mp3_22050_32`, `mp3_24000_48`, `mp3_44100_32/64/96/128/192`, `pcm_8000/16000/22050/24000/32000/44100/48000`, `ulaw_8000`, `alaw_8000`, `opus_48000_32/64/96/128/192` **Non-streaming (`stream: false`):** All of the above, plus `wav_8000/16000/22050/24000/32000/44100/48000` ### Response The response body is raw audio bytes with the `Content-Type` matching the requested format (e.g. `audio/mpeg`, `audio/wav`). ### Examples ```bash theme={null} curl -X POST https://api.meshapi.ai/v1/audio/speech \ -H "Authorization: Bearer rsk_..." \ -H "Content-Type: application/json" \ -d '{ "model": "eleven_flash_v2_5", "input": "Hello! This is a test of the Mesh API text-to-speech endpoint.", "voice": "JBFqnCBsd6RMkjVDRZzb", "response_format": "mp3_44100_128" }' \ --output speech.mp3 ``` ```bash theme={null} curl -X POST https://api.meshapi.ai/v1/audio/speech \ -H "Authorization: Bearer rsk_..." \ -H "Content-Type: application/json" \ -d '{ "model": "eleven_flash_v2_5", "input": "Hello! This is a test.", "voice": "JBFqnCBsd6RMkjVDRZzb", "stream": false, "response_format": "wav_44100" }' \ --output speech.wav ``` ```python theme={null} import httpx response = httpx.post( "https://api.meshapi.ai/v1/audio/speech", headers={"Authorization": "Bearer rsk_..."}, json={ "model": "eleven_flash_v2_5", "input": "Hello! This is a test.", "voice": "JBFqnCBsd6RMkjVDRZzb", "response_format": "mp3_44100_128", }, ) with open("speech.mp3", "wb") as f: f.write(response.content) ``` ```ts theme={null} import fs from "fs"; const res = await fetch("https://api.meshapi.ai/v1/audio/speech", { method: "POST", headers: { Authorization: "Bearer rsk_...", "Content-Type": "application/json", }, body: JSON.stringify({ model: "eleven_flash_v2_5", input: "Hello! This is a test.", voice: "JBFqnCBsd6RMkjVDRZzb", response_format: "mp3_44100_128", }), }); const buffer = await res.arrayBuffer(); fs.writeFileSync("speech.mp3", Buffer.from(buffer)); ``` *** ## WebSocket TTS Streaming `WS /v1/audio/speech/stream/{voice_id}` Stream text-to-speech in real time. You send text chunks as they become available (e.g. as an LLM streams tokens), and receive audio back chunk by chunk — minimising latency compared to the REST endpoint. The streaming frame protocol depends on the model family. The `voice_id` is part of the URL path. * **Standard streaming models** — e.g. `hexgrad/kokoro-82m`, `cartesia/sonic-2`, `cartesia/sonic-3`, `canopylabs/orpheus-3b-0.1-ft` — use the text-buffer protocol. * **ElevenLabs models** (`elevenlabs/*`) use ElevenLabs' native stream-input frames. ### Authentication Pass your Mesh API key in one of two ways: * `Sec-WebSocket-Protocol: Bearer rsk_...` header * `?api_key=rsk_...` query parameter ### Query parameters | Parameter | Default | Description | | :-------------- | :------------------ | :------------------------------------------------------------ | | `model_id` | `eleven_flash_v2_5` | Model to use. Determines the streaming frame protocol. | | `output_format` | `pcm_22050` | Audio format for streamed audio. See supported formats below. | | `language_code` | — | BCP-47 language code. | ElevenLabs models additionally accept `enable_logging` (`true`/`false` logging opt-out), `enable_ssml_parsing` (enable SSML in the input text), `inactivity_timeout` (seconds of inactivity before the session closes, 1–180), `sync_alignment` (return word-level alignment data with each audio chunk), `auto_mode` (optimise for low-latency, fully-automated generation), `apply_text_normalization` (`auto`, `on`, or `off`), and `seed` (reproducible seed, 0–4294967295). ### Message protocol — standard streaming models **Client → server (JSON frames)** | Frame type | Fields | Description | | :------------------------- | :------------- | :------------------------------------- | | `input_text_buffer.append` | `text: string` | Append a chunk of text to the buffer. | | `input_text_buffer.commit` | `{}` | Flush the buffer and finish synthesis. | **Server → client (JSON frames)** | Frame type | Fields | Description | | :------------------------------------- | :----------------------- | :------------------------------------------------------ | | `conversation.item.audio_output.delta` | `delta: string` (base64) | Audio chunk. Decode from base64 to get raw audio bytes. | | `conversation.item.audio_output.done` | `{}` | Signals all audio has been sent. | #### Example ```js theme={null} const ws = new WebSocket( "wss://api.meshapi.ai/v1/audio/speech/stream/af_bella" + "?model_id=hexgrad/kokoro-82m&output_format=pcm_24000&api_key=rsk_..." ); ws.onopen = () => { // 1. Append text chunks ws.send( JSON.stringify({ type: "input_text_buffer.append", text: "Hello, this is streamed text-to-speech.", }) ); // 2. Flush + finish ws.send(JSON.stringify({ type: "input_text_buffer.commit" })); }; ws.onmessage = ({ data }) => { const frame = JSON.parse(data); if (frame.type === "conversation.item.audio_output.delta") { // Decode base64 audio and play / write to file const audioBytes = atob(frame.delta); console.log(`Received ${audioBytes.length} bytes of audio`); } if (frame.type === "conversation.item.audio_output.done") { console.log("Stream complete"); ws.close(); } }; ``` ### Message protocol — ElevenLabs models **Client → server (JSON frames)** | Frame type | Fields | Description | | :--------------------- | :----------------------------------------------------------------------------------------------- | :------------------------------------------------- | | `initializeConnection` | `text: " "`, optional `voice_settings`, `generation_config`, `pronunciation_dictionary_locators` | Must be the first message sent. | | `sendText` | `text: string`, optional `try_trigger_generation`, `voice_settings`, `flush` | Send a chunk of text to synthesize. | | `closeConnection` | `text: ""` | Signal end of input and close the session cleanly. | **Server → client (JSON frames)** | Frame type | Fields | Description | | :------------ | :--------------------------------------------- | :------------------------------------------------------- | | `AudioOutput` | `audio: string` (base64), optional `alignment` | Audio chunk. Decode from base64 to get raw audio bytes. | | `FinalOutput` | `isFinal: true` | Signals all audio has been sent. | | `error` | `message: string` | Sent before closing on auth, format, or upstream errors. | Any credential fields (`xi-api-key`, `authorization`, `api_key`) in client frames are stripped before forwarding upstream — your upstream credentials are never exposed to the client. #### Example ```js theme={null} const ws = new WebSocket( "wss://api.meshapi.ai/v1/audio/speech/stream/JBFqnCBsd6RMkjVDRZzb" + "?model_id=eleven_flash_v2_5&output_format=mp3_44100_128&api_key=rsk_..." ); ws.onopen = () => { // 1. Initialize the connection ws.send(JSON.stringify({ text: " " })); // 2. Stream text chunks ws.send(JSON.stringify({ text: "Hello, this is streamed text-to-speech." })); // 3. Close when done ws.send(JSON.stringify({ text: "" })); }; ws.onmessage = ({ data }) => { const frame = JSON.parse(data); if (frame.audio) { // Decode base64 audio and play / write to file const audioBytes = atob(frame.audio); console.log(`Received ${audioBytes.length} bytes of audio`); } if (frame.isFinal) { console.log("Stream complete"); ws.close(); } }; ``` ### Supported output formats **ElevenLabs models:** `mp3_22050_32`, `mp3_44100_32/64/96/128/192`, `pcm_16000/22050/24000/44100`, `ulaw_8000` **Standard streaming models:** `pcm`, `mp3`, `wav`, `opus`, `aac`, `flac`, each with an optional sample rate (e.g. `pcm_24000`). *** *** ## Together AI voices Together-hosted TTS models (Kokoro, Orpheus, Cartesia Sonic) don't use the ElevenLabs voice catalogue — each model has its own set of voices passed in the same `voice` field. The `/v1/audio/voices` endpoint lists ElevenLabs voices only; use the references below for Together models. ### Kokoro — `hexgrad/kokoro-82m` Pass a voice name such as `af_bella`. Kokoro also supports **voice mixing**: join two or more voices with `+` (e.g. `af_bella+af_heart`), with optional per-voice weights in parentheses (e.g. `af_bella(2)+af_heart(1)`). A selection of the 50+ available voices (prefix key: `a`=American, `b`=British, `j`=Japanese, `z`=Chinese, `e`=Spanish, `f`=French, `h`=Hindi, `i`=Italian, `p`=Portuguese; `f`=female, `m`=male): ``` af_heart af_bella af_nova af_sarah af_sky am_adam am_echo am_michael am_onyx am_puck bf_emma bf_alice bf_lily bm_george bm_lewis bm_daniel jf_alpha jm_kumo zf_xiaoxiao zm_yunxi ef_dora ff_siwis hf_alpha hm_omega ``` ### Orpheus — `canopylabs/orpheus-3b-0.1-ft` One of: `tara`, `leah`, `jess`, `leo`, `dan`, `mia`, `zac`, `zoe`. ### Cartesia Sonic — `cartesia/sonic-2`, `cartesia/sonic-3` Pass the voice **display name** (not a voice ID). 130+ voices are available; a selection of English voices: ``` friendly sidekick nonfiction man newsman newslady calm lady helpful woman reading lady reading man british reading lady british narration lady meditation lady new york man indian lady indian man ``` ```json theme={null} { "model": "cartesia/sonic-3", "input": "Hello from Cartesia Sonic.", "voice": "friendly sidekick" } ``` **Streaming with Together models.** When `stream: true`, Together TTS models only emit raw PCM — set `response_format` to a `pcm_*` value (e.g. `pcm_16000`, `pcm_24000`). For non-streaming requests (`stream: false`) you can also use `mp3_*` or `wav_*`. ## Available voices List available voices (ElevenLabs voices): ```bash theme={null} curl https://api.meshapi.ai/v1/audio/voices \ -H "Authorization: Bearer rsk_YOUR_KEY" ``` You can filter and search using query parameters: | Parameter | Description | | ----------------- | --------------------------------------------------- | | `search` | Full-text search string | | `page_size` | Number of results per page (1–100) | | `next_page_token` | Pagination cursor from previous response | | `voice_type` | Filter by voice type | | `category` | Filter by voice category | | `voice_ids` | Comma-separated list of specific voice IDs to fetch | | `sort` | Sort field | | `sort_direction` | Sort direction | **Response:** ```json theme={null} { "voices": [ {"voice_id": "EXAVITQu4vr4xnSDxMaL", "name": "Sarah", ...}, {"voice_id": "AZnzlk1XvdvUeBnXmlld", "name": "Brian", ...} ], "has_more": false, "next_page_token": null, "total_count": 2 } ``` ## Available models | Model | Provider | Notes | | ------------------------------ | -------- | ---------------------------------------------- | | `openai/tts-1` | OpenAI | Fast, standard quality | | `openai/tts-1-hd` | OpenAI | Higher quality, slower | | `sarvam/bulbul:v3` | Sarvam | Indian languages (Hindi, Tamil, Telugu, etc.) | | `hexgrad/kokoro-82m` | Together | Open-weight, 50+ voices, supports voice mixing | | `canopylabs/orpheus-3b-0.1-ft` | Together | Expressive English voices | | `cartesia/sonic-2` | Together | Cartesia Sonic 2 — 130+ voices | | `cartesia/sonic-3` | Together | Cartesia Sonic 3 (latest) — 130+ voices | Together TTS voices are passed in the `voice` field but follow each model's own naming — see [Together AI voices](#together-ai-voices) above.