OpenAI acquires Promptfoo to secure its AI agents

OpenAI announced Monday it has acquired Promptfoo, an AI security startup founded in 2024 to protect LLMs from online adversaries.

The frontier lab said in a blog post that once the deal closes, Promptfoo’s technology will be integrated into OpenAI Frontier, its enterprise platform for AI agents.

The development of independent AI agents that perform digital tasks has generated excitement about productivity gains. But it’s also given bad actors fresh opportunities to access sensitive data or manipulate automated systems. This deal underscores how frontier labs are scrambling to prove their technology can be used safely in critical business operations.

Promptfoo was founded by Ian Webster and Michael D’Angelo to develop tools that companies can use to test security vulnerabilities in LLMs, including an open-source interface and library. The company reports that its products are used by more than 25% of Fortune 500 companies.

Promptfoo has raised just $23 million since its founding, and was valued at $86 million after its most recent round in July 2025, according to Pitchbook. OpenAI did not disclose the value of the transaction.

OpenAI’s post said Promptfoo’s technology will allow its agent platform to perform automated red-teaming, evaluate agentic workflows for security concerns, and monitor activities for risks and compliance needs. The company also said it expects to continue building out Promptfoo’s open-source offering.