Antithesis, a software-testing startup based in Tysons Corner, Virginia, has secured $105 million in a Series A funding round. The deal, which closed on December 3, 2025, values the company at $525 million. Jane Street led the investment.
The company previously raised $47 million in a 2024 seed round at a valuation of $215 million. Antithesis reports that its annualized recurring revenue has increased more than 12 times over the past two years, reaching approximately $10 million.
The startup plans to allocate the new capital to expand its engineering team, develop platform autonomy features, and scale sales and marketing efforts. The company is currently targeting markets in North America, Europe, and Asia, with its product also available via the AWS Marketplace.
Founded in 2018 by Will Wilson, the company offers a deterministic simulation testing platform. The system creates controlled replicas of production environments to reproduce bugs on demand and performs automatic root-cause analysis.
The company's client base includes firms in finance, AI infrastructure, data platforms, and blockchain protocols, such as Jane Street, MongoDB, and Ethereum. Antithesis is reportedly already considering another funding round due to rising demand.
