Micro1 raises $100 million at $4 billion valuation

San Francisco-based AI startup Micro1 has raised over $100 million in a new funding round, bringing the company’s valuation to $4 billion. The funding, which includes participation from two frontier AI labs and two co-founders of xAI, marks an eightfold increase in valuation from September 2025.

Founded by 25-year-old Ali Ansari, Micro1 pivoted from an AI recruiting business to a provider of high-quality, human-created training data for frontier AI models. The company utilizes AI interviewers to vet domain experts, including engineers, doctors, and lawyers, to supply the data necessary for model training and evaluation.

Micro1’s client base includes Microsoft, Amazon, and robotics firm 1X. The company has also expanded into providing “reinforcement learning gyms,” which are simulated environments using real-world enterprise data to allow AI agents to practice workplace navigation.