Diffblue, creators of the world’s first fully autonomous generative AI-for-code software, announced it has secured €5.8 million in new capital as it reaches a record six-month period with 326% net new ARR growth from the prior six months. Toffer Winslow (formerly StackState, Dynatrace, RSA Security) has also been appointed as Diffblue’s new CEO to drive the firm’s next stage of growth.
Diffblue’s new and oversubscribed round of funding was anchored by existing investors IP Group, Parkwalk Advisors, and AlbionVC, with additional participation from Oxford University, and private investors via the Oxford Technology and Innovations EIS Fund (OTIF). Additionally, Citi Institutional Strategic Investments joined as a new equity investor. The company is now well-positioned to continue to fuel its triple-digit growth rate well into 2026 while still maintaining a capital efficient approach that is uncommon among generative AI companies.
The company’s rapid top-line growth is driven by swift and steady customer adoption of Diffblue’s AI-powered autonomous test generation platform that catches bugs early in the development cycle when they are easy and inexpensive to fix. Diffblue’s novel approach is different from LLMs and supports the mission of developers and IT leaders who are committed to automating intelligently, shortening release cycles, and delivering better quality software for the benefit of users. Today, Diffblue serves four of the 10 largest U.S. banks and several other members of Forbes’ Global 2000. Key customers include: Citi, ING, Cisco, AstraZeneca, and The Bank of New York Mellon Corporation (BNY).
“There is a massive market opportunity for start-ups that figure out how to harness the potential of AI to transform how software gets built, tested, and deployed,” said Iain Maclean, Global Head of Rates Technology at Citi. “Our investment in the company reflects our belief in its potential to be an important player in the next generation of AI-powered software development tools.”
Founded by researchers from the University of Oxford, Diffblue drives velocity, quality, and productivity for Java development teams working on mission-critical applications. Its flagship product, Diffblue Cover, leverages generative AI to automate unit test generation 250x faster than a human developer. As a result, software teams can improve code quality, expand test coverage, and increase efficiency so they can ship software faster, more frequently, and with fewer defects. Diffblue’s differentiated approach to generative AI leverages reinforcement learning techniques to avoid the accuracy, security, privacy, and liability concerns associated with LLM-based coding assistants.
“Diffblue is leading the charge in one of the hottest, fastest-moving markets in the history of the software industry,” added Mark Reilly, Managing Partner at IP Group. “The company’s traction with large, sophisticated customers deploying best-in-class AI technologies across their software development processes is strong evidence of its differentiated, valuable solution.”
“Diffblue is at a hugely exciting juncture owing to its team’s ability to provide a valuable solution within a rapidly evolving market,” said Neil Cameron, Investment Director at Parkwalk. “At Parkwalk, we invest in companies with the potential to lead transformative industries. Diffblue’s growth, coupled with its increasing traction amongst global customers, only strengthens our confidence in their long-term impact on the future of software development.”
Toffer Winslow, CEO at Diffblue, added, “Diffblue’s deterministic AI technology, committed employees, blue chip customers, and visionary investors are a rare and enviable foundation on which a great company can be built. I’m grateful for all the good work that has been done to build the company to-date and excited for the opportunity ahead as we build a market leader in our space.”