FastChat vs New API
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 | New API |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 69 · Good | 100 · Excellent |
| Category | Local LLM Runners | Local LLM Runners |
| License | Apache-2.0 | MIT |
| Language | Python | Go |
| Setup difficulty | Hard | Medium |
| Min. RAM | 8,192 MB | 512 MB |
| Deployment | docker, source | docker |
| GitHub stars | ★ 39,550 | ★ 48,815 |
| First released | 2023 | 2024 |
| Replaces | OpenAI API | OpenRouter, OpenAI API |
What are FastChat and New API?
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
New API
New API is a large-model interface management and distribution system derived from One API, providing an OpenAI-compatible gateway with richer billing, rendering and provider support. It is designed for running a self-hosted AI relay service.
- OpenAI-compatible relay
- Multi-provider channels
- Detailed billing
- Modern dashboard
FastChat vs New API: key differences
FastChat is written in Python, while New API is built with Go. Licensing differs — Apache-2.0 for FastChat versus MIT for New API. New API is the lighter option, starting around 512 MB of RAM against 8,192 MB for FastChat.
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 New API if…
- OpenAI-compatible gateway
- Broad provider support
- Built-in billing and quotas
Watch out for
- Docs primarily Chinese
- Niche relay use case
Frequently asked questions
Is FastChat or New API better?
New API is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider FastChat if its specific feature set fits your needs better.
Are FastChat and New API free and open-source?
Yes. FastChat is licensed under Apache-2.0 and New API under MIT. Both can be self-hosted at no software cost.
Can I run FastChat and New API with Docker?
FastChat: yes. New API: yes.
Which is lighter on resources, FastChat or New API?
New API has the smaller minimum footprint at 512 MB of RAM, compared to about 8,192 MB for FastChat. Real-world usage depends on library size, user count, and enabled features.