FastChat
Distributed multi-model LLM serving system with web UI and OpenAI-compatible APIs.
Pricing
Free tier
Flat rate
Adoption
↘CoolingLicense
Open Source
Data freshness
Aging · Jun 8, 2026Overview
What is FastChat?
FastChat is a distributed system for serving large language models, offering both a web interface and RESTful APIs compatible with OpenAI. It's designed to support multiple models and provide scalable performance.
Key differentiator
“FastChat stands out as an open-source, distributed system with both web UI and OpenAI-compatible APIs, making it ideal for developers needing flexibility in serving multiple large language models.”
Capability profile
Capability Radar
Honest assessment
Strengths & Weaknesses
↑ Strengths
↓ Weaknesses
API requires Python-specific patterns, TypeScript SDK is community-maintained
v0.1 to v0.2 migration required rewriting chain definitions
Advanced configuration options are not well-documented, leading to trial-and-error usage
Scalability issues reported when serving models larger than 10B parameters under heavy load
Fit analysis
Who is it for?
✓ Best for
Teams needing to serve and scale multiple large language models simultaneously
Developers looking for an OpenAI-compatible API for their projects
Projects requiring a web interface alongside RESTful APIs for LLM access
✕ Not a fit for
Users who prefer fully managed cloud services without self-hosting requirements
Applications that require real-time streaming capabilities (batch-only architecture)
Cost structure
Pricing
Free Tier
Available
Open source — free to use
Starts at
$0
Model
Flat rate
Enterprise
None
Performance benchmarks
How Fast Is It?
Ecosystem
Relationships
Works well with
Next step
Get Started with FastChat
Step-by-step setup guide with code examples and common gotchas.