Kokoro TTS is the flagship engine on OfflineTTS, offering 54 voices across 9 languages including English, Japanese, Chinese, Spanish, French, Hindi, Italian, and Portuguese. Powered by an 82M parameter StyleTTS 2 model with ISTFTNet, it delivers the highest quality speech synthesis available in a browser.

It supports multiple model sizes (q4 ~90MB, q8 ~300MB, fp32 ~600MB) and runs on both WebGPU and WASM backends, automatically selecting the fastest option for your device.