Arena, the AI leaderboard everyone uses, is now a $100M business

Arena, known for its free crowdsourced AI model leaderboard, launched a paid service called AI Evaluations last September. Eight months in, it hit $100M in annualized run-rate revenue. The leaderboard draws from over 10 million user blind votes comparing model outputs. The post doesn't disclose customer count or pricing details.

Why it matters: Arena going from free leaderboard to $100M ARR hits all three HKR axes with concrete numbers and timeline. Kept at 78 rather than higher because the post doesn't disclose customer count or pricing — can't tell if that $100M is 10 big clients or 1,000 smaller ones.