Synthesize Speech

Synthesize speech from text in a single request. Pass `text` + `voice_id`, get back binary audio. Pick the model with the `model` body parameter: default `lightning_v3.1`, or `lightning_v3.1_pro` for the Pro pool. Other request parameters are identical across models. **Language behaviour on `lightning_v3.1_pro`:** pass `language: en` for UK + American accented English, pass `language: hi` for Indian accented English + Hindi (code-switching), or omit `language` to default to `en + hi` (mixed Indian + Western English coverage). On `lightning_v3.1` the full 12-language catalog applies (see voice catalog). ## When to use this - **Use this** for short utterances you can render before playback (notifications, prompts, batch jobs, audio file generation). - **Use `/waves/v1/tts/live`** when you want playback to start before the full audio is ready (long passages, latency-sensitive apps). - **Use `/waves/v1/tts/live`** (WebSocket) when text arrives incrementally (LLM token streams, live captioning). ## Key features - 44 kHz natural, expressive synthesis - Model selectable per request via `model` body parameter - Cloned voice IDs (`voice_*`) work on `lightning_v3.1` — same param as catalog voices - 12 documented languages on `lightning_v3.1`. On `lightning_v3.1_pro`: `language: en` → UK + American accented English; `language: hi` → Indian accented English + Hindi; omit `language` → defaults to `en + hi`. - Output formats: `pcm`, `mp3`, `wav`, `ulaw`, `alaw` - Sample rates: 8 kHz – 44.1 kHz - Speed: 0.5× – 2× - Per-call pronunciation dictionaries via `pronunciation_dicts` ## Examples **cURL — Lightning v3.1 (default)** ```bash curl -X POST "https://api.smallest.ai/waves/v1/tts" \ -H "Authorization: Bearer $SMALLEST_API_KEY" \ -H "Content-Type: application/json" \ -H "Accept: audio/wav" \ -d '{ "text": "Hello from Waves TTS.", "voice_id": "magnus", "sample_rate": 24000, "output_format": "wav" }' --output speech.wav ``` **cURL — Lightning v3.1 Pro (omit `language` → defaults to `en + hi`)** ```bash curl -X POST "https://api.smallest.ai/waves/v1/tts" \ -H "Authorization: Bearer $SMALLEST_API_KEY" \ -H "Content-Type: application/json" \ -H "Accept: audio/wav" \ -d '{ "text": "Hello from the Lightning v3.1 Pro pool.", "voice_id": "meher", "model": "lightning_v3.1_pro", "sample_rate": 24000, "output_format": "wav" }' --output speech.wav ``` **cURL — Lightning v3.1 Pro with explicit `language: en` (UK + American accented English)** ```bash curl -X POST "https://api.smallest.ai/waves/v1/tts" \ -H "Authorization: Bearer $SMALLEST_API_KEY" \ -H "Content-Type: application/json" \ -H "Accept: audio/wav" \ -d '{ "text": "Good morning, this is a Pro voice speaking.", "voice_id": "meher", "model": "lightning_v3.1_pro", "language": "en", "sample_rate": 24000, "output_format": "wav" }' --output speech.wav ``` **cURL — Lightning v3.1 Pro with explicit `language: hi` (Indian accented English + Hindi)** ```bash curl -X POST "https://api.smallest.ai/waves/v1/tts" \ -H "Authorization: Bearer $SMALLEST_API_KEY" \ -H "Content-Type: application/json" \ -H "Accept: audio/wav" \ -d '{ "text": "Namaste, this is an Indian-accented Pro voice.", "voice_id": "meher", "model": "lightning_v3.1_pro", "language": "hi", "sample_rate": 24000, "output_format": "wav" }' --output speech.wav ``` ## Common gotchas - **Set `Accept: audio/wav`.** Omitting it can return an empty or unplayable response. - **Pair voice IDs with the right model.** Voice catalogs differ between `lightning_v3.1` and `lightning_v3.1_pro`. The API does not reject mismatched pairings, but using a Pro-only `voice_id` with `model=lightning_v3.1` (or omitting `model`) can return wrong or hallucinated audio. Pair Pro voices with `model=lightning_v3.1_pro`; standard catalog voices with `model=lightning_v3.1` (the default). - **Cloned voices** (`voice_*` from `add_voice`) work with `lightning_v3.1` only; voice cloning is not available on `lightning_v3.1_pro`. - **44.1 kHz output** is supported but most playback environments are happy with 24 kHz — drop the sample rate if bandwidth matters.