Best Browser Text to Speech 2026

Which browser text-to-speech engine is the best in 2026? We compare Kokoro, Piper, Kitten, and Supertonic across quality, speed, model size, language support, and real-world use cases — so you can pick the right one for your project.

All four engines run entirely in your browser. No API keys, no server calls, no data uploads. They differ in quality, speed, voice count, and ideal use cases.

Quick comparison table:

| | Kokoro | Piper | Kitten | Supertonic | |---|---|---|---|---| | Quality | A/A- (best) | C+ (good) | C+ (good) | B (good) | | Voices | 54 | 25 curated (+904) | 8 expressions | 10 styles | | Languages | 9 | 1 (English) | 1 (English) | 5 | | Model size | ~90-600MB | ~75MB | ~24MB | Varies | | Speed | 1-2x realtime | 3-5x realtime | 1-2x realtime | 1-2x realtime | | Backend | WebGPU + WASM | WASM only | WebGPU + WASM | WebGPU + WASM | | Sample rate | 24kHz | 22.05kHz | 8-48kHz | Configurable | | Best for | Best quality | Fastest CPU | Lightest | Multilingual | | License | Apache 2.0 | MIT | Apache 2.0 | Supertone |

When to use Kokoro TTS: Kokoro is the best choice for most users. Its 82M parameter StyleTTS 2 model produces the highest quality speech, with 54 voices across 9 languages. If you need natural-sounding audio for YouTube, podcasts, audiobooks, or presentations, Kokoro delivers the best results. Heart (A-rated) and Bella (A-rated) are the top voices.

When to use Piper TTS: Piper is the best choice when speed matters more than quality. It generates audio 3-5x faster than realtime on CPU alone — no WebGPU needed. Use Piper for bulk generation, Home Assistant integration, accessibility tools, or any scenario where you need fast, serviceable speech on any device.

When to use Kitten TTS: Kitten is the best choice for lightweight or mobile use. At just 24MB, it loads in seconds and runs on virtually any device. Its 8 expression-based voices (cheerful, serious, sad, whisper, excited, gentle, calm, neutral) give you creative control that raw voice selection doesn't. Use Kitten for prototyping, mobile, embedded hardware, and ASMR-style content.

When to use Supertonic TTS: Supertonic is the best choice for multilingual content in its supported languages (English, Spanish, Portuguese, French, Korean). Its 10 preset voice styles (5 male, 5 female) provide consistent quality across all supported languages.

Bottom line: Start with Kokoro for the best quality. Switch to Piper for speed or Kitten for size. Use Supertonic for its supported languages.