ChatTTS
ChatTTS is a generative speech synthesis model optimized for dialogue and conversational AI applications. It supports English and Chinese with fine-grained control over prosodic features like laughter, pauses, and intonation, delivering natural-sounding speech from text.
Key facts
Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.
| Field | Value |
|---|---|
| Repository | 2noise/ChatTTS |
| Owner | 2noise |
| Primary language | Python |
| License | AGPL-3.0 — OSI-approved |
| Stars | 39.6k |
| Forks | 4.2k |
| Open issues | 63 |
| Latest release | v0.2.5 (2026-04-10) |
| Last updated | 2026-04-10 |
| Source | https://github.com/2noise/ChatTTS |
What ChatTTS is
A PyTorch-based TTS model trained on 100,000+ hours of multilingual audio data, with a publicly available 40,000-hour pre-trained variant. Provides token-level and word-level prosodic control through special markup, supports multiple speaker embeddings via Gaussian sampling, and includes streaming audio generation capabilities.
Get the ChatTTS source
Clone the repository and explore it locally.
git clone https://github.com/2noise/ChatTTS.gitcd ChatTTS# follow the project's README for install & configurationNeed it deployed, integrated, or customized instead? DEV.co ships production installs.
Best use cases
Implementation considerations
- AGPL-3.0 code license is copyleft; any derivative work or integration requires source disclosure and same license, or formal licensing exception. Not suitable for closed-source commercial products without review.
- Model weights (CC BY-NC 4.0) are explicitly non-commercial only; for-profit use is prohibited without separate commercial licensing agreement.
- Pre-trained model is intentionally degraded (MP3 compression, high-frequency noise) to deter misuse; audio quality expectations should be set accordingly.
- Python/PyTorch stack; GPU recommended for inference speed. Installation includes optional vLLM, FlashAttention-2, and TransformerEngine, but latest versions of these are noted as unrecommended/under development.
- Active maintenance as of April 2026; v0.2.5 released recently. 39k+ stars suggest community interest, but formal SLAs and support channels are not standard.
When to avoid it — and what to weigh
- Commercial Production Without Legal Review — AGPL-3.0 code license requires source code disclosure; model is CC BY-NC 4.0 (non-commercial only). Commercial use requires formal licensing review—contact [email protected].
- Non-English/Chinese Language Support Required — Currently supports English and Chinese only. Roadmap indicates more languages are coming, but they are not yet available.
- Production Quality Audio Without Optimization — Open-source 40k-hour model is pre-trained only (no supervised fine-tuning) and intentionally compressed with MP3 and high-frequency noise to limit misuse. Expect lower quality than internal 100k-hour version.
- Systems Requiring Guaranteed Output Quality & Reliability — Project is ~2 years old; model reliability assertions and SLAs are not provided. Authors explicitly state they do not guarantee accuracy or completeness.
License & commercial use
Dual licensing: Code is AGPL-3.0 (strong copyleft, source disclosure required); pre-trained model weights are CC BY-NC 4.0 (non-commercial use only). Commercial use requires formal licensing review and likely separate agreement.
Code (AGPL-3.0) is not suitable for closed-source commercial products without source disclosure or licensing exception. Model weights (CC BY-NC 4.0) explicitly prohibit commercial use. For-profit deployment is not permitted under current licenses. Contact [email protected] for formal commercial licensing inquiries. Requires legal review before any commercial production use.
DEV.co evaluation signals
Editorial assessment — not user reviews. Directional, with an explicit confidence level.
| Signal | Assessment |
|---|---|
| Maintenance | Active |
| Documentation | Adequate |
| License clarity | Needs review |
| Deployment complexity | Moderate |
| DEV.co fit | Good |
| Assessment confidence | High |
No formal security audit results published. Authors intentionally added high-frequency noise and MP3 compression to discourage misuse for unauthorized voice synthesis. Plan to open-source a detection model for identifying ChatTTS-generated audio. No documented vulnerability disclosure policy or security contact. Use of pre-trained weights from Hugging Face introduces supply-chain dependency. Recommendation: conduct code review and model validation before production deployment; review AGPL-3.0 copyleft obligations if integrating into proprietary systems.
Alternatives to consider
Coqui TTS (tts library)
Open-source, permissive Apache 2.0 license, commercial-friendly. Supports multiple languages. Lower prosody control granularity; less optimized for dialogue scenarios but more deployment-flexible.
Google Cloud Text-to-Speech / Microsoft Azure Speech Services
Proprietary SaaS; commercial licenses clear and well-defined. Enterprise SLA, multiple languages, production-grade reliability. Higher cost and latency; no on-premise option.
Bark (Suno)
Open-source, MIT license, commercial-friendly. Supports multiple languages and fine-grained control. Lower maturity and community adoption; different training data and prosody model; less dialogue-optimized.
Build on ChatTTS with DEV.co software developers
Explore ChatTTS for conversational AI, but verify license compliance for your use case. For commercial deployment, contact the 2noise team to discuss licensing terms.
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ChatTTS FAQ
Can we use ChatTTS in a commercial product?
What languages does ChatTTS support?
Is the open-source model the same quality as the internal one?
Do you offer support or SLAs?
Custom software development services
DEV.co helps companies turn open-source tools like ChatTTS into production software. Our software development services cover the full lifecycle — architecture, web development, integration, and maintenance — delivered by software developers and web developers who ship. Engage our software development agency to implement or customize it for your ai frameworks stack.
Ready to Add Natural Speech to Your Dialogue Application?
Explore ChatTTS for conversational AI, but verify license compliance for your use case. For commercial deployment, contact the 2noise team to discuss licensing terms.