Snorkel AI valued at $3.5 billion amid surging demand for complex AI training data

Data startup Snorkel AI has raised $350 million in fresh funding at a $3.5 billion valuation, its CEO Alex Ratner told Reuters, as booming demand from frontier AI labs for increasingly complex ‌training data and simulated environments fuels rapid growth.

Led by Insight Partners and S32, the funding round included participation ‌from existing investors Addition, Greylock and Wells Fargo, the company said. The deal values the company at nearly three times the $1.3 billion valuation achieved when ​it last raised $100 million in May 2025.

The San Francisco-based company said its annualized revenue run-rate has crossed $350 million, from roughly $20 million a year earlier, driven by the data-as-a-service business it launched in September 2025.

Founded in 2019 by a team of researchers spinning out of the Stanford AI lab, Snorkel AI initially sold software but has shifted toward supplying finished datasets and reinforcement-learning, or RL, environments ‌directly to customers.