Harvey buys Guardrails AI as it raises $550 million at a $15.5 billion valuation

Harvey said Guardrails co-founders Shreya Rajpal and Zayd Simjee and their team will join its product and engineering organization to work on applied AI projects. Terms were not disclosed. Guardrails maintains an open-source guardrails framework that Harvey said is downloaded more than 250,000 times a month, and Snowglobe, a simulation environment in which synthetic users stress-test agents to expose failures before real users encounter them. Harvey described the deal as its fourth acquisition of 2026.

The funding round was co-led by Diffusion and Lightspeed Venture Partners, with new investors Sapphire Ventures and Whale Rock joining existing backers including Sequoia, Kleiner Perkins, Andreessen Horowitz, Coatue, GIC and Goldman Sachs Alternatives, according to Harvey. TechCrunch reported that the company was valued at $11 billion in a $200 million round in March and has now raised more than $1.5 billion. Harvey said 80 percent of Am Law 100 firms and five Fortune 10 companies use its products. LawSites, citing co-founder Winston Weinberg, reported that annual recurring revenue has passed $400 million across more than 3,000 customers.