OpenAI has announced plans to acquire Promptfoo, an AI security and evaluation platform used by enterprise development teams to test and harden AI systems before deployment. Financial terms were not disclosed.
Promptfoo's technology will be integrated into OpenAI Frontier, the company's platform for building and operating AI coworkers. The acquisition is a clear signal that OpenAI views security and governance capabilities as foundational requirements for enterprise adoption of agentic AI — not optional add-ons.
Founded in 2024 by Ian Webster and Michael D'Angelo, Promptfoo was built to give developers a systematic way to test AI applications. The founders say adversarial testing for security, safety, and behavioural risks quickly emerged as the biggest blocker to enterprise AI deployment.
Promptfoo raised an $18.4 million Series A in July 2025, led by Insight Partners and including Andreessen Horowitz, and had a post-money valuation of $85.5 million at that point, according to Pitchbook. By the time of the acquisition, more than 350,000 developers had used the platform, with 130,000 active monthly users and adoption across more than a quarter of Fortune 500 companies.
Once integrated into Frontier, the technology is expected to provide automated red-teaming, vulnerability detection for risks including prompt injections, jailbreaks, data leaks, and out-of-policy agent behaviour, and governance reporting to support enterprise oversight requirements.
OpenAI has stated it will continue to maintain Promptfoo's open-source project.
The acquisition follows a pattern of OpenAI filling platform gaps through targeted purchases as it accelerates its enterprise push. The company also acquired healthcare tech startup Torch in January 2026, and previously acquired Software Applications, maker of the Sky AI interface for Mac.