Snorkel AI secures $350 million, lifts valuation to $3.5 billion amid AI data surge

Snorkel AI, a data-as-a-service startup founded in 2019 by researchers from the Stanford AI lab, closed a $350 million funding round that values the company at $3.5 billion, nearly triple its $1.3 billion valuation from the previous round in May 2025. Led by Insight Partners and S32, the round also included existing backers Addition, Greylock and Wells Fargo. The San Francisco-based firm reported that its annualized revenue run-rate has surged past $350 million, up from about $20 million a year earlier, after it began selling finished datasets and reinforcement-learning environments in September 2025.

Snorkel’s “agentic data development platform” pairs human experts with thousands of AI models to create and verify data, serving frontier AI labs, hyperscalers, enterprises and the U.S. federal government, with coding data among its biggest growth areas. CEO Alex Ratner said the influx of demand reflects AI developers’ shift toward more complex, high-stakes training data that still requires human input, while synthetic and automated methods handle scale. The fresh capital will be used to recruit researchers and engineers, broaden enterprise and government operations, support third-party AI model evaluations and explore new industry verticals, with the company targeting profitability this year.