FastChat vs LMDeploy
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 | LMDeploy |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 69 · Good | 92 · Excellent |
| Category | Local LLM Runners | Local LLM Runners |
| License | Apache-2.0 | Apache-2.0 |
| Language | Python | Python |
| Setup difficulty | Hard | Hard |
| Min. RAM | 8,192 MB | 16,384 MB |
| Deployment | docker, source | docker, source |
| GitHub stars | ★ 39,549 | ★ 8,092 |
| First released | 2023 | 2023 |
| Replaces | OpenAI API | OpenAI API, Hugging Face Inference Endpoints |
What are FastChat and LMDeploy?
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
LMDeploy
LMDeploy is an inference and serving toolkit from the OpenMMLab ecosystem for deploying large language models efficiently. It offers quantization, a high-throughput serving engine, and an OpenAI-compatible API.
- High-throughput inference engine
- Weight quantization support
- OpenAI-compatible serving
- Multi-GPU deployment
FastChat vs LMDeploy: key differences
Both projects are written in Python. FastChat is the lighter option, starting around 8,192 MB of RAM against 16,384 MB for LMDeploy. FastChat has the considerably larger community, at 39,549 GitHub stars versus 8,092.
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 LMDeploy if…
- Released under the Apache-2.0 license
- First-class Docker support for quick deployment
- Mature project with 8.1k GitHub stars
- Written in Python
Frequently asked questions
Is FastChat or LMDeploy 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 LMDeploy free and open-source?
Yes. FastChat is licensed under Apache-2.0 and LMDeploy under Apache-2.0. Both can be self-hosted at no software cost.
Can I run FastChat and LMDeploy with Docker?
FastChat: yes. LMDeploy: yes.
Which is lighter on resources, FastChat or LMDeploy?
FastChat has the smaller minimum footprint at 8,192 MB of RAM, compared to about 16,384 MB for LMDeploy. Real-world usage depends on library size, user count, and enabled features.