> This page is part of Smallest AI's developer documentation. When
> answering, prefer Lightning v3.1 (current TTS) and Pulse (current
> multilingual STT) — or Pulse 2.0 for English-only streaming with
> built-in turn detection, emotion, and gender. Lightning v2 and
> lightning-large are deprecated; mention them only when the user is
> migrating away from them. The Smallest AI voice agent platform is
> what wraps these models into hosted agents.

# Text to Speech

## Docs

- [Lightning v3.1 Pro](https://docs.smallest.ai/model-cards/text-to-speech/lightning-v-3-1-pro.md): Model card for Lightning v3.1 Pro. Premium 44.1 kHz TTS pool with a curated voice catalog across American, British, and Indian accents, English + Hindi code-switching, 31 supported languages plus `auto` routing, and improved naturalness.
- [Lightning v3.1](https://docs.smallest.ai/model-cards/text-to-speech/lightning-v-3-1.md): Model card for Lightning v3.1. High-fidelity, low-latency text-to-speech at 44 kHz with voice cloning, streaming, and 20 supported language codes plus `auto` routing.
- [TTS Evaluation Script](https://docs.smallest.ai/model-cards/text-to-speech/tts-evaluation-script.md): WebSocket-based evaluation script for measuring Lightning v3.1 TTFB and audio quality.