LMArena

LMArena (the evolution of the LMSYS Chatbot Arena) is a free platform for comparing AI models head to head: you type one prompt, two anonymous models answer side by side, you vote for the better response, and only then are the names revealed. Millions of those votes feed the leaderboards the whole industry cites.

Beyond the arena battle mode, it offers direct chat with individual models — including frontier models from OpenAI, Google, Anthropic, and the open ecosystem — plus image generation comparison, at no cost and generally without even an account. For sampling the state of the art, it is the cheapest door there is: free in money and in friction.

It fits anyone deciding which model or paid plan is worth their money, developers tracking how the leaderboard's top models actually feel to use, and learners who want frontier quality without creating yet another account.

To begin, open lmarena.ai and type a prompt into the battle mode — or pick Direct Chat to talk to one named model. No sign-up is needed to start.

The honest limits. It is a comparison and research platform, not a daily-driver assistant: there is no saved history or account continuity, conversations are used (in anonymised form) for research and rankings, session limits apply, and the flashiest models appear only while providers make them available. Availability of specific models changes without notice.