Design Arena’s co-founder Grace Li started her company with a simple goal: make AI games fun. Her solution? Human feedback at scale.

The platform, now used by 5.3 million people, has caught the eye of major investors like Index Ventures and A*. For non-enterprise users, Design Arena acts as a sophisticated model router, offering ‘A vs B’ choices until the best outcome is ranked. The real magic happens on the enterprise side, where AI models receive instant feedback to improve their output.

With a current annual recurring revenue of $60 million and a growing user base, Design Arena stands out as a critical source for human-led evaluation in the AI industry. But not all ventures in this space are successful — Yupp’s failure last year serves as a cautionary tale about building sustainable long-term businesses.

The future of AI seems to depend on more than just machine learning; it also needs an understanding of what humans truly desire. As Li notes, ‘there was no substitute for human judgment’ and that still rings true today.