Snorkel AI raises $350M Series E at $3.5B valuation as training-data demand surges

Snorkel AI has closed a $350 million Series E that values the company at $3.5 billion, up from the $1.3 billion valuation attached to its $100 million Series D roughly 17 months earlier.

The round was led by Insight Partners and S32, with existing backers Addition, Lightspeed, Greylock, GV and Wells Fargo also participating.

Founded seven years ago, Snorkel initially sold software that automated data labeling. Last year it changed course to deliver completed datasets to customers, a model it markets as data-as-a-service.

The company does not rely solely on a marketplace of human experts. It uses a hybrid approach in which its own software and models generate data synthetically while subject matter experts contribute alongside that output. It also builds training datasets and simulated environments for AI labs and corporate clients.

Snorkel said its annualized revenue run rate has reached $375 million, an eighteenfold increase over the past 12 months. The company attributes that growth to AI labs' demand for high-end training data.

Other firms pitching themselves as AI data labs have posted comparable expansion. Mercor's gross annualized revenue has reached $2 billion, Handshake crossed the $1 billion mark earlier this year, and Micro1 has scaled to $500 million.