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Building community trust with open science is critical for the development of AI and its alignment with the needs and preferences of all users. With that in focus, we’re delighted to publish Arena-Rank, an open-source Python package for ranking that powers the LMArena leaderboard!

Arena Expert is a great way to differentiate between frontier models. In this analysis, we compare how models perform on 'general' vs 'expert' prompts, focusing on 'thinking' vs 'non-thinking' models.

Since launching the platform, developing a rigorous and scientifically grounded evaluation methodology has been central to our mission. A key component of this effort is providing proper statistical uncertainty quantification for model scores and rankings. To that end, we have always reported confidence intervals alongside Arena scores and surfaced any

Introducing Code Arena: live evals for agentic coding in the real world AI coding models have evolved fast. Today’s systems don’t just output static code in one shot. They build. They scaffold full web apps and sites, refactor complex systems, and debug themselves in real time. Many now

The next frontier of large language model (LLM) evaluation lies in understanding how models perform when challenged by expert-level problems, drawn from real work, across diverse disciplines.

Since we first introduced categories over two years ago, and Vision Arena last year, the AI evaluation landscape has evolved. New categories have been added, existing ones have been updated, and the leaderboards they power are becoming more insightful with each round of community input.

“Nano-Banana” is the codename that was used on LMArena during testing for what is now known as: Gemini 2.5 Flash Image. Try it for yourself directly on LMArena.ai

Search Arena on LMArena goes live today, read more about what we've learned so far about human preference with the search-augmented data.

At LMArena, everything starts with the community. There have been a lot of new members joining us in the past few months so we thought it would be a good time to reintroduce ourselves! Created by researchers from UC Berkeley’s SkyLab, LMArena is an open platform where everyone can

About a month ago, we announced that LMArena was becoming a company to better support our growing community platform. As we take this next step, we're staying true to our original mission of rigorous, neutral, and community-driven evaluations. Today, we’re excited to share that we’ve raised