Arena, the AI leaderboard everyone uses, just became a 100 million dollar business

Arena, the crowdsourced AI leaderboard that started as a UC Berkeley research project in 2023, has reached 100 million dollars in annualized revenue just eight months after launching its first commercial product. The platform is best known for letting users compare two anonymous AI model responses side by side and vote on which is better. More than 10 million of those evaluations have now been submitted.

The revenue comes from AI Evaluations, a paid service Arena introduced in September that gives model labs and enterprises detailed performance analytics drawn from its community of users. By December, the service had reached 30 million dollars in annualized revenue. It has more than tripled since then.

There is a caveat in the headline number. While Arena describes the figure as ARR, CEO Anastasios Angelopoulos told TechCrunch that customers pay for consumption, meaning the revenue is not recurring in the traditional SaaS sense. “A lot of people don’t even understand that our business is making any money at all, they still see us as like an open-source project,” he said.

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Arena has no direct competitor left standing. Yupp, the only other crowdsourced AI model-picking startup, shut down in March after raising 33 million dollars from a16z crypto’s Chris Dixon. Angelopoulos said Arena competes “for the same dollar” as human labeling companies like Mercor, Surge, and Scale AI, all of which help model makers refine their AI during post-training.

That market is growing fast. Handshake’s annualized revenue from AI training nearly doubled from 550 million dollars in January to nearly one billion dollars by April, according to The Information. Mercor’s annualized revenue also topped one billion dollars earlier this year, though a supply chain breach has since complicated its relationship with key clients including Meta.

Arena was co-founded by Angelopoulos and Wei-Lin Chiang, both postdoctoral researchers at UC Berkeley, along with Ion Stoica, the UC Berkeley professor and Databricks co-founder who advised the project before it incorporated in April 2025. The company raised 150 million dollars in a Series A round in January at a valuation of nearly two billion dollars, bringing its total funding to 250 million dollars from investors including Felicis, Andreessen Horowitz, Kleiner Perkins, and Lightspeed.

The platform now ranks AI models across text, coding, vision, and image generation, as well as complex agent workflows through a recently introduced Agent Mode. Its leaderboard has become the de facto scorecard for frontier AI models, with labs from OpenAI to Anthropic to Google routinely citing Arena rankings in their own launch announcements. Turning that influence into a 100 million dollar business in under a year suggests that evaluating AI may be nearly as lucrative as building it.