AfterQuery Hits $3.2B Valuation as YC's Fastest Unicorn

The San Francisco-based startup AfterQuery has reportedly raised a new funding round that values the company at $3.2 billion. This milestone comes just five months after the company announced its $30 million Series A round at a $300 million valuation in April. The new figure represents a tenfold increase in valuation in less than half a year. According to Y Combinator partner Gustaf Alströmer, this rapid rise makes AfterQuery the fastest startup to transition from launch to unicorn status in the history of the accelerator.

Led by founders who are currently 22 and 23 years old, AfterQuery graduated from Y Combinator's Winter 2025 cohort just 18 months ago. The startup's financial trajectory has been equally steep; in April, the company disclosed that it had already achieved an annualized revenue run rate of $100 million. AfterQuery has quickly built a high-profile client roster that includes major industry players such as Nvidia, Legora, and the South Korean artificial intelligence lab Motif Technologies.

While other data-labeling and training startups like Scale AI and Mercor focus heavily on ensuring that models generate accurate answers, AfterQuery takes a different approach to training. The company hires highly specialized knowledge professionals, including doctors and lawyers, to teach AI models and agents how to replicate professional workflows. Rather than simply correcting factual errors, these specialists help the systems learn by "encoding the patterns, decisions, and reasoning of the world’s best practitioners."

For AI practitioners and developers, AfterQuery's methodology represents a shift from static data validation to behavioral alignment. By training agents on the actual decision-making processes of human experts, developers can build more autonomous systems capable of handling complex, multi-step professional tasks. This approach could significantly reduce the time required to fine-tune specialized enterprise agents, allowing developers to deploy AI that behaves like an experienced colleague rather than a simple search tool.