# Smallest.ai Lightning TTS (slim)

> Smallest AI's Lightning text-to-speech API turns text into 44.1 kHz speech over HTTP, server-sent events or WebSocket, with the Lightning v3.1 and v3.1 Pro models in up to 31 languages, pronunciation dictionaries and word timestamps.

- Full: https://www.anchorterminal.com/tools/smallest-lightning-tts.md (~8,200 tokens) · this version ~1,680 tokens · JSON https://www.anchorterminal.com/tools/smallest-lightning-tts.json · canonical https://www.anchorterminal.com/tools/smallest-lightning-tts
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-07 · pricing https://www.anchorterminal.com/tools/smallest-lightning-tts#pricing · reviews https://www.anchorterminal.com/tools/smallest-lightning-tts#reviews
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

**B · 64.4/100 · rank #469 of 1486 · #9 in Text-to-speech · not agent-ready · confidence medium**


Assessment: Lightning streams speech over HTTP, SSE or WebSocket with OpenAPI and AsyncAPI files and public prices of $0.175 to $0.195 per 10,000 characters. The default model retires on 30 November with 28 days' notice, published concurrency limits disagree, and the shared API failed in every region on five days in September.

## Facts

- Kind: Model API · vendor: Smallest AI · category: Text-to-speech · legal entity: Smallest, Inc. · provenance 87/100
- Local only (HTTP, websocket): pypi `smallestai`, npm `smallestai`, npm `@developer-smallestai/smallest-mcp-server`
- Auth: API key · pricing: Pay per use · x402: no · licence: unknown
- Benchmark probes: not run yet, so Performance is pending
- Vendor status page: not read, no machine-readable status found (2026-11-07 04:48 UTC)
- Surface listed: The Lightning text-to-speech routes of the Models API at api.smallest.ai/waves/v1, read from docs.smallest.ai (Markdown pages, llms.txt, OpenAPI and AsyncAPI files, changelog), smallest.ai pricing, terms and privacy pages and status.smallest.ai on 6 November 2026. No account was made and no request was sent to the API
- Models: `lightning_v3.1_pro` (stable, curated voices, 31 languages plus `auto`), `lightning_v3.1_pro_10_26` (preview for English, Spanish and Hindi until 28 November) and `lightning_v3.1` (217 voices, retiring 30 November 2026)
- Controls: Speed, sample rate, eight output formats including PCM, WAV and MP3, number pronunciation language, date order, opt-in maths reading, a profanity filter, pronunciation dictionaries and word timestamps on the WebSocket. No SSML
- Text limit: 8,000 characters per request after trimming
- Regions: Mumbai and Oregon, routed by proximity, with region-pinned hosts api.india.smallest.ai and api.us.smallest.ai
- MCP server: `@developer-smallestai/smallest-mcp-server` 0.11.2 (MIT, npm) runs locally with npx and mostly manages voice agents, with `text_to_speech` and `get_voices` tools among about 80
- Other products: Pulse speech to text (listed separately), Hydra speech to speech, the Electron LLM, instant voice cloning and the Atoms voice agent platform share the same key and quota
- SDKs: Python `smallestai` 5.14.0 (7 October 2026); streaming users of `WavesStreamingTTS` need 5.1.1 or later before the v3.1 retirement. The npm `smallestai` Node SDK is at 1.0.1, last published in May 2025
- Prices: Lightning v3.1 $17.50 per 1M characters; Lightning v3.1 Pro $19.50 per 1M characters

- Scores: Reliability 58, Performance pending, Schema & documentation 92, Agent ergonomics 72, Security & auth 52, Payments & pricing 40, Task success pending, Maintenance & community 68, Transparency & trust 70 · total over the 7 assessed categories
- Why: Reliability, BetterStack status page at status.smallest.ai with components for the Global, India and USA APIs (one health check covers the Agents and Mod… · Schema & documentation, OpenAPI 3.1 for the sync and SSE routes and AsyncAPI 2.6 for the WebSocket, with request and event schemas (25). · Agent ergonomics, API reading of the checklist. · Security & auth, Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. · Payments & pricing, No x402, MPP or L402 (0). · Maintenance & community, Read as a model. · Transparency & trust, Closed service with clear terms naming Smallest Inc.
- Sources: 18, open questions: 5, both in the full twin
- Capabilities: speech.tts, speech.streaming, speech.voices, speech.languages
- JSON: https://www.anchorterminal.com/api/v1/tools/smallest-lightning-tts.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/smallest-lightning-tts.svg` or a link to https://www.anchorterminal.com/tools/smallest-lightning-tts from a page on smallest.ai or one of its subdomains, or the README at the root of github.com/smallest-inc/smallest-python-sdk, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.
- Support: Discord https://discord.com/invite/xNBrdjdBa6; support@smallest.ai; https://docs.smallest.ai/voice-agents/resources/getting-help; https://status.smallest.ai/; more in the full twin

## Before you call it

1. Always send `"model": "lightning_v3.1_pro"`, since requests with no model go to a model that retires on 30 November 2026
2. Pick voices from `GET /waves/v1/lightning-v3.1-pro/get_voices`, because the v3.1 and v3.1 Pro catalogues differ
3. Keep each request under 8,000 characters and split longer text
4. Treat 429 as the concurrency ceiling and retry with backoff from 500 ms to 30 s, honouring Retry-After
5. Fix names and acronyms with a pronunciation dictionary, since SSML isn't accepted

## Connect

```bash
pip install smallestai
```

```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 Smallest AI.", "voice_id": "meher", "model": "lightning_v3.1_pro", "sample_rate": 24000, "output_format": "wav"}' \
  --output hello.wav
```

```bash
claude mcp add smallest -- npx -y @developer-smallestai/smallest-mcp-server
```

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Deepgram Text-to-Speech (Aura-2, Flux TTS) | BB | 75.6 | speech.tts, speech.streaming, speech.voices, speech.languages | https://www.anchorterminal.com/tools/deepgram-tts.min.md |
| Amazon Polly | BB | 75.4 | speech.tts, speech.streaming, speech.voices, speech.languages | https://www.anchorterminal.com/tools/amazon-polly.min.md |
| ElevenLabs Text to Speech API + MCP | BB | 75.3 | speech.tts, speech.streaming, speech.voices, speech.languages | https://www.anchorterminal.com/tools/elevenlabs-tts.min.md |
| HeyGen Voice | BB | 73.6 | speech.tts, speech.streaming, speech.voices, speech.languages | https://www.anchorterminal.com/tools/heygen-voice.min.md |
| Azure AI Speech text-to-speech | BB | 71.5 | speech.tts, speech.streaming, speech.voices, speech.languages | https://www.anchorterminal.com/tools/azure-text-to-speech.min.md |


## Panel reviews (0, desk reviews from public material, no calls made)