AI Training Data Startup AfterQuery Raises $30M at $300M Valuation

Quick Facts

• AfterQuery raised $30M Series A at $300M valuation with Altos Ventures leading the round
• Company reached $100M annual revenue run rate just 14 months after Y Combinator graduation
• Platform partners with 100,000 verified professionals to create expert reasoning datasets for AI model training

AfterQuery announced a $30 million Series A round at a $300 million valuation. Altos Ventures led the investment, with The Raine Group joining existing investors Y Combinator and BoxGroup.

The company reached a $100 million annual revenue run rate in just 14 months since graduating from Y Combinator’s Winter 2025 batch. AfterQuery works with nearly 100,000 verified professionals across finance, healthcare, law, and software engineering to create high-quality training datasets for AI models.

Founded in January 2025 by Spencer Mateega, Carlos Georgescu, and Danny Tang, AfterQuery operates as an applied research lab focused on curating expert reasoning datasets. The company says every major AI lab now uses its services.

“We are excited to have the support of both new and existing investors as we make expertise that once took a lifetime to build available to anyone,” said Spencer Mateega, co-founder and CEO. “We are also proud to share that AfterQuery has surpassed $100 million in annual revenue run rate.”

AfterQuery offers two main products: expert reasoning datasets and training environments where AI models practice decision-making in realistic professional scenarios. The company’s validation-first approach shows measurable improvements before clients access the data.

The startup competes with Scale AI, valued at $13.8 billion in its last funding round, and Appen. AfterQuery differentiates itself by focusing on structured reasoning from verified experts rather than crowdsourced data annotation.

The AI training dataset market reached $3.2 billion in 2025 and is projected to grow to $16.3 billion by 2033, according to market research. Rising AI deployment across industries has boosted dataset demand by 39% as companies prioritize model accuracy.

AfterQuery will use the funding to expand its expert network, cover more specialized domains, and build enterprise solutions. The company also plans to strengthen its engineering and research teams.

The investor base includes angels from Anthropic, OpenAI, DeepMind, Meta, and Microsoft. “Human data is an enormous market and critical bottleneck for frontier models,” said an Altos Ventures representative.

Read more: AI training data startup AfterQuery nabs $30M investment