LMArena, the open community platform for evaluating the best AI models, has secured $100 million in seed funding led by a16z and UC Investments (University of California) with participation from Lightspeed, Laude Ventures, Felicis, Kleiner Perkins and The House Fund. In a space moving at breakneck speed, LMArena is building something foundational: a neutral, reproducible, community-driven layer of infrastructure that allows researchers, developers, and users to understand how models actually perform in the real world. Over four hundred model evaluations have already been made on the platform, with over 3 millions votes cast, helping shape both proprietary and open-source models across the industry, including those from Google, OpenAI, Meta, and xAI. The new LMArena includes: a rebuilt UI, mobile-first design, lower latency, and new features like saved chat history and endless chat. The legacy site will remain live for a while, but all future innovation is happening on lmarena.ai. Backers say what makes LMArena different is not just the product, but the principles behind it. Evaluation is open, the leaderboard mechanics are published, and all models are tested with diverse, real-world prompts. This approach makes it possible to explore in-depth how AI performs across a range of use cases.