# Supertonic

> Fast, lightweight on-device text-to-speech running locally via ONNX Runtime.

Supertonic is an open-source, on-device text-to-speech model built to execute fast local inference without relying on cloud APIs or dedicated GPUs. Operating via ONNX Runtime with a compact 99M-parameter footprint, it produces 44.1kHz audio across 31 languages on hardware ranging from desktop CPUs to Raspberry Pis. Note that the original repository has been archived, though code and weights remain usable under the MIT license.

Website: https://github.com/supertone-inc/supertonic

## What it is for

- Run offline, low-latency text-to-speech synthesis directly on user devices without API costs.
- Convert long web articles into spoken audio inside browser extensions in under a second.
- Add speech playback to resource-constrained devices like Raspberry Pi boards or e-readers.
- Integrate multilingual speech synthesis across mobile apps using iOS, Flutter, or native SDKs.

## Features

- Lightweight ONNX architecture requiring no GPU and running entirely offline.
- Multilingual support covering 31 languages, including a language-agnostic auto-detection mode.
- High-quality audio generation directly outputting 44.1kHz 16-bit WAV files.
- Native handling of complex numbers, currency, dates, and technical abbreviations.
- Inline expression tags like laughter, breaths, and sighs to adjust vocal nuance.
- Broad language bindings including Python, Node.js, WebGPU, Rust, Go, C++, C\#, Java, Swift, and Flutter.

## Pricing

Open source. Free and open-source under the MIT license.

## Details

- Type: GitHub repo
- Category: [AI](https://xiry.app/topics/ai.md)
- Topic: [Text to Speech](https://xiry.app/topics/ai/text-to-speech.md)
- Open source: yes
- Platforms: macOS, Windows, Linux, iOS, Android, Web, Browser extension, Code library, Command line
- For: Developers building offline, edge-native, or privacy-focused audio applications.
- Alternative to: ElevenLabs, OpenAI TTS
- Tags: tts, speech synthesis, onnx, on device, voice, audio

## Why it was saved

- [@marc.kaz, 13 May 2026](https://www.instagram.com/reel/DYQj-k2ObE4/): Eliminates cloud TTS API costs and latency, running 167x faster than real-time on Apple Silicon and operating efficiently even on low-power devices like Raspberry Pi and e-readers.

## Compare

- [Alternatives to ElevenLabs](https://xiry.app/alternatives/elevenlabs.md)

## Related

- [ElevenLabs](https://xiry.app/resources/elevenlabs): AI voice generator, voice cloning, and conversational agent platform (Web app, Freemium)
- [Cartesia Sonic](https://xiry.app/resources/cartesia-sonic): Ultra-low-latency streaming text-to-speech and instant voice cloning model. (AI model, Freemium)
- [Dia](https://xiry.app/resources/dia): Open-source 1.6B text-to-speech model generating multi-speaker dialogue in one pass. (AI model, Open source)
- [Airy](https://xiry.app/resources/airy): Fast, low-cost text-to-speech API and studio for creators and developers (AI model, Freemium)
- [AudioPen](https://xiry.app/resources/audiopen): Converts spoken thoughts into structured, polished writing in customizable styles. (Web app, Freemium)
- [cartesia-python](https://xiry.app/resources/cartesia-python): Official Python library for Cartesia's real-time text-to-speech API (GitHub repo, Paid)

Updated 3 October 2026. Page: https://xiry.app/resources/supertonic

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