FastChat vs Petals
A side-by-side comparison of two self-hosted local llm runners options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | FastChat | Petals |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 69 · Good | 24 · At risk |
| Category | Local LLM Runners | Local LLM Runners |
| License | Apache-2.0 | MIT |
| Language | Python | Python |
| Setup difficulty | Hard | Hard |
| Min. RAM | 8,192 MB | 8,192 MB |
| Deployment | docker, source | source, docker |
| GitHub stars | ★ 39,550 | ★ 10,585 |
| First released | 2023 | 2022 |
| Replaces | OpenAI API | OpenAI API |
What are FastChat and Petals?
FastChat
FastChat is an open platform for training, serving, and evaluating large language model chatbots. It powers the Chatbot Arena and provides an OpenAI-compatible API server for self-hosted models.
- OpenAI-compatible API
- Web UI for model chat
- Distributed serving
- Model evaluation tools
Petals
Petals lets you run and fine-tune large language models in a distributed, BitTorrent-style network where each participant hosts part of the model. It enables self-hosting models too large for a single machine.
- Distributed model hosting
- Run models larger than one GPU
- Collaborative inference swarm
- Fine-tuning support
FastChat vs Petals: key differences
Both projects are written in Python. Licensing differs — Apache-2.0 for FastChat versus MIT for Petals. FastChat has the considerably larger community, at 39,550 GitHub stars versus 10,585.
Why pick each one
Choose FastChat if…
- OpenAI-compatible API
- Powers Chatbot Arena
- Multi-model serving
Watch out for
- GPU recommended
- Steep learning curve
Choose Petals if…
- Released under the MIT license
- First-class Docker support for quick deployment
- Mature project with 10.6k GitHub stars
- Written in Python
Frequently asked questions
Is FastChat or Petals better?
Neither is universally better. FastChat has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are FastChat and Petals free and open-source?
Yes. FastChat is licensed under Apache-2.0 and Petals under MIT. Both can be self-hosted at no software cost.
Can I run FastChat and Petals with Docker?
FastChat: yes. Petals: yes.