Snorkel AI raises $350M Series E at $3.5B valuation as AI training data demand surges
Snorkel AI says its annualized revenue run rate surged 18-fold to $375 million in 12 months, driven by demand for high-end training data. The company shifted to data-as-a-service last year, delivering complete datasets and reinforcement-learning environments.
Snorkel AI has closed a $350 million Series E round at a $3.5 billion valuation, nearly tripling the $1.3 billion valuation it held just 17 months ago when it raised a $100 million Series D.
The round, announced in September 2026, was led by Insight Partners and S32. Existing investors — including Addition, Lightspeed, Greylock, GV, and Wells Fargo — also participated.
Founded in 2019 following four years of research by co-founder and CEO Alex Ratner and his team at a Stanford AI lab, Snorkel helps AI labs and corporations build training datasets and simulated environments. The company originally offered software for data labeling automation but shifted last year to a data-as-a-service model, delivering completed datasets to customers. Its approach combines software and models to generate data synthetically alongside subject matter experts, rather than relying solely on a human expert marketplace.
Snorkel reports an annualized revenue run-rate of $375 million — an 18-fold increase over the past 12 months. The company attributes that growth to strong demand from AI labs for high-end training data. Because Snorkel sells reinforcement learning environments and complete datasets rather than human labor, payments to its human experts are counted as cost of goods sold rather than included in its top-line revenue figures.
Other companies in the AI data space have reported similar growth trajectories. Mercor’s gross annualized revenue has reached $2 billion, Handshake crossed the $1 billion mark earlier in 2026, and Micro1 has scaled to $500 million. However, those figures are gross revenue, and since such companies pay out roughly 60% to 70% directly to domain specialists, their net revenue is substantially lower than headline numbers suggest.
The fundraise signals continued investor appetite for companies supplying the training data that underpins AI development, with Snorkel’s rapid valuation growth suggesting the data-as-a-service model may be gaining traction as a differentiated approach in the space.