---
title: "Generate speech from text"
method: POST
path: "/v0/assistant/voice/generate"
tags: ["Voices"]
---

# Generate speech from text

`POST /v0/assistant/voice/generate`

Generates audio from text using the specified provider and voice.

## Request body

- VoiceGenerateRequest
  - `text` string, required — Text to synthesize.
  - `provider` 'cartesia' | 'elevenlabs' | 'openai', required — TTS provider.
  - `voice_id` string, required — Provider-specific voice ID for the speech.
  - `model_id` string, nullable — Provider-specific model ID (e.g., 'sonic-2' for Cartesia, 'eleven_multilingual_v2' for ElevenLabs, 'gpt-4o-mini-tts' for OpenAI).
  - `output_format` 'mp3' | 'wav' | 'flac' | 'pcm_s16le' | 'pcm_mulaw' — Desired audio output format. This will determine the Content-Type of the response.
  - `cartesia_language` string, nullable — Language code for Cartesia TTS (e.g., 'en'). If None, Cartesia attempts auto-detection.
  - `cartesia_sample_rate` integer, nullable — Optional sample rate for Cartesia (e.g., 24000, 44100). Provider defaults used if None.
  - `cartesia_bit_rate` integer, nullable — Optional bit rate for Cartesia lossy formats like MP3 (e.g., 128000). Provider defaults used if None. Not for PCM.
  - `elevenlabs_optimize_streaming_latency` integer, nullable — 0-4. Optimize for streaming latency for ElevenLabs.
  - `elevenlabs_voice_settings_stability` number, nullable — Stability for ElevenLabs voice settings.
  - `elevenlabs_voice_settings_similarity_boost` number, nullable — Similarity boost for ElevenLabs voice settings.

## Response `200`

Audio generated successfully. Content-Type will be audio/mpeg, audio/wav, etc.

- unknown

## Other responses

- `400` — Bad Request (e.g., invalid provider, provider API error)
- `422` — Validation Error
- `503` — Service unavailable (e.g. provider API down)

---

[API](https://skmtc.net/unify/apis/unifyai-http-api-reference.md) · [All operations](https://skmtc.net/unify/apis/unifyai-http-api-reference/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/unify/unifyai-http-api-reference/versions/900377f918b6/schema)