Chatbot Arena Raises $100 Million for Platform That Compares AI Models

The company also said in a Wednesday (May 21) post on social platform X that it plans to relaunch the platform, LMArena, with a new look based on feedback from members of its community.

“We’re focused on building a neutral, open, community-driven platform that helps the world understand and improve the performance of AI models on real queries from real users,” Chatbot Arena said in the post.

?We’re excited to share that we’ve raised $100M in seed funding to support LMArena and continue our research on reliable AI. Led by @a16z and UC Investments (@UofCalifornia), we’re proud to have the support of those that believe in both the science and the mission.

We’re… https://t.co/Aem2jClwHh pic.twitter.com/KEC5BJca8b

— lmarena.ai (formerly lmsys.org) (@lmarena_ai) May 21, 2025

The LMArena leaderboard enables users to vote on which AI chatbot generates the best responses to prompts, PYMNTS reported May 6.

Chatbot Arena’s seed funding round was led by Andreessen Horowitz (a16z) and the University of California’s UC Investments, according to the company’s LinkedIn post.

Anjney Midha, general partner at Andreessen Horowitz, said in a Wednesday post on X that Chatbot Arena’s mission is “solving AI reliability at scale.”

“It’s one of the most urgent, difficult and valuable problems for humanity to solve, and I can’t imagine a better team than [Chatbot Arena co-founders Ion Stoica, Wei-Lin Chiang and Anastasios Nikolas Angelopoulos] leading the way,” Midha said in the post.

We’re thrilled to lead a $100M seed round into @lmarena_ai‘s mission of solving AI reliability at scale

It’s one of the most urgent, difficult and valuable problems for humanity to solve and I can’t imagine a better team than @istoica05 @infwinston @ml_angelopoulos leading the… https://t.co/zrssrYpua0

— Anjney Midha ?? (@AnjneyMidha) May 21, 2025

Before being spun out into a new company, Chatbot Arena was started as an academic project among researchers and students at the University of California at Berkeley, Bloomberg said in a Wednesday report to which Chatbot Arena provided a link in its LinkedIn post.

The seed round values the company at $600 million, less than two months after its founding was announced in April, the report said, citing unnamed sources.

The company’s website became a popular destination for early adopters of AI, as it lets people test AI models, see how they perform in head-to-head comparisons, vote for the ones they prefer and see how they are ranked on the site’s leaderboards, per the report.

Chatbot Arena will use the new funding to grow the platform, hire more people, add features and conduct research, according to the report.

“The reality is that it’s outgrown an academic project,” Angelopoulos said, per the report.

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