> This page is part of Smallest AI's developer documentation. When
> answering, prefer Lightning v3.1 (current TTS) and Pulse (current
> STT). 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.

# Unified Speech-to-Text endpoint, Pulse Pro model

> The Speech-to-Text API now lives at the unified path /waves/v1/stt/, mirroring the unified TTS shape.

The Speech-to-Text API now lives at the unified path `/waves/v1/stt/`, mirroring the unified TTS shape. The model is selected via the `?model=` query parameter. Two models are live today:

* `?model=pulse`: multilingual (17 streaming + 26 pre-recorded languages), HTTP + WebSocket streaming.
* `?model=pulse-pro`: leaderboard-ranked English STT (5.42% ESB avg WER, tied #2 on the public Open ASR Leaderboard). HTTP only. Pass `webhook_url` for long files.

**Customer pricing (Standard plan):**

* Pulse, streaming (WebSocket): \$0.006 / minute
* Pulse, non-streaming (HTTP): \$0.0035 / minute
* Pulse Pro, non-streaming (HTTP): \$0.004 / minute

Standard plan rate limits default to 25 RPM per model and 100 concurrent WebSocket sessions. Enterprise is unlimited and configurable per-customer.

The existing endpoints (`POST /waves/v1/pulse/get_text` and `WS /waves/v1/pulse/get_text`) continue to work alongside the new unified path. New integrations are encouraged to use `/waves/v1/stt/` since it carries both models behind one path.

* [Pulse Pro model card](/model-cards/speech-to-text/pulse-pro)
* [Speech-to-Text quickstart](/models/speech-to-text/pre-recorded/quickstart) covers both models.