Antithesis has raised a $105 million Series A funding round led by Jane Street, marking a significant step in the company’s effort to make deterministic simulation testing a core component of modern software reliability. The round includes participation from Amplify Venture Partners, Spark Capital, Tamarack Global, First In Ventures, Teamworthy Ventures, Hyperion Capital, and individual investors such as Patrick Collison, Dwarkesh Patel, and Sholto Douglas, as well as other new and returning backers. Jane Street is both an investor and a customer, a rare combination for the trading firm.
The financing will help Antithesis accelerate product development, expand its engineering organization, and scale its go-to-market operations across North America, Europe, and Asia. The company also plans to deepen its availability through cloud channels, including AWS Marketplace.
Antithesis positions its platform as a replacement for traditional example-based testing, arguing that it is inadequate for the complexity and scale of modern software systems. As organizations adopt increasingly distributed architectures and AI accelerates the pace of code development, Antithesis offers a deterministic, automated simulation engine that compresses months of real-world behavior into hours.
The platform searches for edge cases, injects faults, validates correctness, and reproduces failures exactly, enabling engineering teams to fix issues more efficiently.
The company already works with customers operating critical, high-stakes systems. Jane Street relies on Antithesis to validate components central to its global trading operations. Ethereum used the platform to simulate extreme network conditions ahead of The Merge, identifying issues that could have threatened the blockchain’s transition to Proof-of-Stake.
MongoDB uses Antithesis to test core components of its database platform to detect subtle issues before deployment. Antithesis reports that its revenue has grown more than twelvefold over the past two years as adoption spreads across finance, AI infrastructure, blockchain, and data platforms.
Founded in 2018 and publicly launched in 2024, the Northern Virginia-based company aims to establish deterministic validation as the default expectation in software development. With its new capital infusion, Antithesis plans to expand engineering capacity, increase platform autonomy, grow sales and marketing teams, and broaden global availability.
KEY QUOTES
“Software now underpins everything, and as systems become more complex and distributed, the world needs a new testing model that guarantees correctness. With this funding, we’re expanding the infrastructure that makes reliability not just achievable, but expected, just as we expect traffic lights to work every time. Our customers are already proving that deterministically validated systems ship faster, without breaking, and earn deeper trust.”
Will Wilson, CEO of Antithesis
“Jane Street runs some of the most demanding distributed systems in the world, and Antithesis has helped us uncover issues that no other testing method could find. We hold a very high bar for the technology we rely on, and an even higher bar for the companies we choose to invest in. While leading an early round is rare for us, Antithesis is years ahead, and we believe deterministic simulation testing will become foundational across industries.”
Doug Patti, Engineer at Jane Street
