Snorkel AI has raised $350M at a $3.5B valuation, nearly tripling the $1.3B mark it reached 17 months ago.
Insight Partners and S32 led the Series E. New backers included March Capital, Blumberg Capital, Allegis Capital, Frontline, Standard and Third Point Ventures, while Greylock, Lightspeed, GV, Factory, Prosperity7, Walden Catalyst and Wells Fargo returned.
The seven-year-old San Francisco company started as a labeling-software vendor and pivoted last year to selling finished datasets and reinforcement-learning environments, a model it calls data-as-a-service. Annualized revenue climbed from roughly $20M to more than $350M in about twelve months.
Labs increasingly need specialist examples for coding, law and medicine, plus realistic simulated tasks and grading rubrics. Snorkel pairs tens of thousands of human experts with automated quality control, and says its customers include frontier labs, hyperscalers, large enterprises and the US federal government.
Chief executive Alex Ratner argues human judgement stays central. Every dataset labs will pay for keeps some human input, he says, but all of it must lean on synthetic and automated methods to keep pace with the complexity.
The market got hotter after Meta paid $14.3B for 49% of Scale AI in June 2025, with Mercor, Surge AI and Micro1 drawing capital from investors chasing the layer between the labs and the expertise they buy.
