TTSLab – A voice AI agent and TTS lab running in the browser via WebGPU

I built TTSLab — a free, open-source tool for running text-to-speech and speech-to-text models directly in the browser using WebGPU and WASM.

No API keys, no backend, no data leaves your machine.

When you open the site, you'll hear it immediately — the landing page auto-generates speech from three different sentences right in your browser, no setup required.

You can then try any model yourself: type text, hit generate, hear it instantly. Models download once and get cached locally.

The most experimental feature: a fully in-browser Voice Agent. It chains speech-to-text → LLM → text-to-speech, all running locally on your GPU via WebGPU. You can have a spoken conversation with an AI without a single network request.

Currently supported models: - TTS: Kokoro 82M, SpeechT5, Piper (VITS) - STT: Whisper Tiny, Whisper Base

Other features: - Side-by-side model comparison - Speed benchmarking on your hardware - Streaming generation for supported models

Source: https://github.com/MbBrainz/ttslab (MIT)

Feedback I'd especially like: 1. How does performance feel on your hardware? 2. What models should I add next? 3. Did the Voice Agent work for you? That's the most experimental part.

Built on top of ONNX Runtime Web (https://onnxruntime.ai) and Transformers.js — huge thanks to those communities for making in-browser ML inference possible.