ModelRefs / LMSYS — AI Glossary
LMSYS — AI Glossary
The Large Model Systems Organization; a UC Berkeley research group operating Chatbot Arena and producing Vicuna, FastChat, and SGLang.
Overview
LMSYS (Zheng, Sheng, et al.) created the Chatbot Arena (crowdsourced Elo ranking), Vicuna (early GPT-4-quality open model), FastChat (inference server), and SGLang (structured generation runtime). Their ELO leaderboard is the most cited production-quality model ranking. Collaboration between UC Berkeley RISE Lab and CMU.
Reference details
| Topic | evaluation |
|---|---|
| Last reviewed | 2026-06-24 |
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Frequently asked questions
What is LMSYS?
The Large Model Systems Organization; a UC Berkeley research group operating Chatbot Arena and producing Vicuna, FastChat, and SGLang.
What concepts are related to LMSYS?
Closely related concepts include chatbot arena, alpacaeval, open llm leaderboard.