FastChat provides tools for end-to-end LLM development, from supervised fine-tuning to deployment and evaluation. The platform powers popular open models like Vicuna and includes specialized components for chatbot serving. Researchers appreciate the modular architecture supporting custom training methods, while product teams leverage the optimized inference stack. The project includes reference implementations for RLHF, multi-modal extensions, and API-compatible serving. FastChat is particularly valuable for organizations developing domain-specific language models or needing transparent alternatives to closed APIs.