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_<your-key> on all REST requests. WebSocket endpoints accept the key via Sec-WebSocket-Protocol: Bearer <rsk_...> or ?api_key=<rsk_...>.

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. Gemini TTS models take a prebuilt voice name (default `Kore`).
`speaker`	string	`ritu`	Speaker name for Sarvam models (`sarvam/bulbul:v3`). 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

curl (streaming)
curl (non-streaming WAV)
Python
Node.js

curl -X POST https://api.meshapi.ai/v1/audio/speech \
  -H "Authorization: Bearer rsk_..." \
  -H "Content-Type: application/json" \
  -d '{
    "model": "elevenlabs/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

curl -X POST https://api.meshapi.ai/v1/audio/speech \
  -H "Authorization: Bearer rsk_..." \
  -H "Content-Type: application/json" \
  -d '{
    "model": "elevenlabs/eleven_flash_v2_5",
    "input": "Hello! This is a test.",
    "voice": "JBFqnCBsd6RMkjVDRZzb",
    "stream": false,
    "response_format": "wav_44100"
  }' \
  --output speech.wav

import httpx

response = httpx.post(
    "https://api.meshapi.ai/v1/audio/speech",
    headers={"Authorization": "Bearer rsk_..."},
    json={
        "model": "elevenlabs/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)

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: "elevenlabs/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

Session limits

Each WebSocket session reserves $10 of your balance while it is open, released when it closes; a session your balance cannot cover is refused with “Insufficient balance to start a session.” An account can hold 5 concurrent WebSocket sessions at once, shared with realtime and streaming speech-to-text sessions.

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

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

const ws = new WebSocket(
  "wss://api.meshapi.ai/v1/audio/speech/stream/JBFqnCBsd6RMkjVDRZzb" +
    "?model_id=elevenlabs/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. GET /v1/audio/voices lists them alongside the ElevenLabs voices (filter with brand or model), and the references below cover the common ones.

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

{
  "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

GET /v1/audio/voices returns one catalogue of TTS voices across model brands: ElevenLabs, Cartesia, Kokoro, Orpheus and others.

curl "https://api.meshapi.ai/v1/audio/voices?brand=hexgrad" \
  -H "Authorization: Bearer rsk_YOUR_KEY"

All filters are optional and case-insensitive:

Parameter	Description
`brand`	Model brand, e.g. `elevenlabs`, `hexgrad`, `canopylabs`, `cartesia`
`model`	A model ID, e.g. `hexgrad/kokoro-82m`. ElevenLabs voices are not tied to a model, so a `model` filter alone drops them; use `brand=elevenlabs`
`search`	Substring match on voice ID or name

Response:

{
  "voices": [
    {
      "voice_id": "af_bella",
      "name": "Bella",
      "brand": "hexgrad",
      "model": "hexgrad/kokoro-82m",
      "language": "en-us",
      "gender": "female",
      "preview_url": null
    }
  ],
  "count": 1,
  "truncated": false
}

The whole list comes back in one response, with no pagination. ElevenLabs voices carry model: null (they work with every ElevenLabs model). truncated: true means a brand’s list was cut short, so the catalogue is partial. A brand that fails to load is skipped rather than failing the request.

Available models

Model	Provider	Notes
`gpt-4o-mini-tts`	OpenAI	OpenAI TTS
`elevenlabs/eleven_flash_v2_5`	ElevenLabs	Low latency
`elevenlabs/eleven_multilingual_v2`	ElevenLabs	Multilingual
`elevenlabs/eleven_v4` / `elevenlabs/eleven_v4_turbo`	ElevenLabs	Eleven v4
`google/gemini-2.5-flash-tts`	Google	Gemini TTS. `response_format`: `pcm_24000`, or `wav_24000` with `stream: false`
`google/gemini-3.1-flash-tts`	Google	Gemini TTS
`google/gemini-3.8-flash-tts` / `google/gemini-3.8-flash-lite-tts`	Google	Gemini TTS
`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 above. Check GET /v1/models for the full live list of TTS models.

Introduction

Accounts & Access

Core Inference

Retrieval & Search

Multimodal

Operations

Mesh Code

Mesh CLI

Platform

Reference

Text to Speech

Audio Generation

Text-to-Speech

Request body

Supported output formats

Response

Examples

WebSocket TTS Streaming

Authentication

Session limits

Query parameters

Message protocol — standard streaming models

Example

Message protocol — ElevenLabs models

Example

Supported output formats

Together AI voices

Kokoro — `hexgrad/kokoro-82m`

Orpheus — `canopylabs/orpheus-3b-0.1-ft`

Cartesia Sonic — `cartesia/sonic-2`, `cartesia/sonic-3`

Available voices

Available models

​Audio Generation

​Text-to-Speech

​Request body

​Supported output formats

​Response

​Examples

​WebSocket TTS Streaming

​Authentication

​Session limits

​Query parameters

​Message protocol — standard streaming models

​Example

​Message protocol — ElevenLabs models

​Example

​Supported output formats

​Together AI voices

​Kokoro — hexgrad/kokoro-82m

​Orpheus — canopylabs/orpheus-3b-0.1-ft

​Cartesia Sonic — cartesia/sonic-2, cartesia/sonic-3

​Available voices

​Available models

Audio Generation

Text-to-Speech

Request body

Supported output formats

Response

Examples

WebSocket TTS Streaming

Authentication

Session limits

Query parameters

Message protocol — standard streaming models

Example

Message protocol — ElevenLabs models

Example

Supported output formats

Together AI voices

Kokoro — `hexgrad/kokoro-82m`

Orpheus — `canopylabs/orpheus-3b-0.1-ft`

Cartesia Sonic — `cartesia/sonic-2`, `cartesia/sonic-3`

Available voices

Available models