LMArena

Originally launched by the UC Berkeley Large Model Systems Organization (LMSYS) as an academic side project, LMArena has evolved into a company that helps answer the question of which AI models are best. It does so by allowing site visitors to compare anonymous AI responses to the same prompt and vote on which one they think is stronger. This provides LMArena a growing dataset of human preferences around AI answers, an alternative to the static benchmarks traditionally used to rank model companies. With over 3 million comparisons logged and over 400 models evaluated as of April 2025, LMArena has become a popular method for comparing and evaluating AI model performance.