Supertonic is a text-to-speech system that runs locally on devices using ONNX Runtime for on-device inference without cloud dependencies.
The tool addresses the need for fast, private speech synthesis by executing entirely on the user's hardware. It uses a compact 99-million-parameter open-weight model that requires no GPU and produces 44.1kHz audio output directly. The system supports 31 languages and can operate in language-agnostic mode when the input language is unknown. It includes expression tags such as laugh, breath, and sigh to add natural variation to synthesized speech without requiring reference audio or prompt engineering.
Supertonic suits projects requiring low-latency audio generation across desktop, mobile, browser, and edge devices like Raspberry Pi or e-readers. The lightweight model footprint makes it practical for resource-constrained environments and enables fast cold starts. Developers should be aware that the repository has announced archival with no further development or official support planned, and associated services will become inaccessible after a specified date. The tool provides multi-runtime SDKs covering Python, Node.js, WebGPU, Java, C++, C#, Go, Swift, iOS, Rust, and Flutter, making it accessible across diverse development environments.
The project shows active maintenance with regular updates and examples across multiple programming languages and platforms. Development activity demonstrates broad platform coverage through working implementations in both compiled and interpreted languages. The codebase maintains support for diverse runtime environments from web browsers to mobile operating systems and embedded systems.
