IndexTTS is an industrial-level, open-source text-to-speech system built for controllable, efficient zero-shot voice synthesis. Give it a short reference recording and a line of text, and it clones the voice and speaks new content in that voice, across languages. The project has gathered over 24,000 stars on GitHub and was updated in September 2026.
IndexTTS is developed by the Index team and published openly with its model weights and code. It focuses on the problems that make TTS hard in production: accurate pronunciation, natural pacing, emotional control, and stable long-form generation. Its zero-shot design means no per-speaker training is required, and cross-lingual support lets a voice recorded in one language speak in another. The system builds on modern vocoder technology such as BigVGAN for high-fidelity audio output, and it is designed to run efficiently enough for real products, not just demos.
IndexTTS is free and open source: you can download the code and model weights from GitHub and run everything on your own hardware at no cost.
IndexTTS suits developers building voice products, creators who need narration in a consistent voice, and researchers working on speech synthesis. If you want production-grade voice cloning without depending on a closed API, it is one of the strongest open options.