OpenAI announced on Monday that it has acquired Promptfoo, an AI security startup founded in 2024 to protect LLMs from online adversaries.
Frontier Lab said in a blog post 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 performing digital tasks has generated excitement about productivity gains. But it has also given bad actors new opportunities to access sensitive data or manipulate automated systems. The deal underlines how leading laboratories are struggling to prove that their technology can be used safely in critical business functions.
PromptFu was founded by Ian Webster and Michael D’Angelo to develop tools that companies can use to test security vulnerabilities in LLM, including open-source interfaces and libraries. The company reports that its products are used by more than 25% of Fortune 500 companies.
According to PitchBook, PromptFu has raised just $23 million since its founding, and was valued at $86 million after its most recent round in July 2025. OpenAI did not disclose the value of the transaction.
OpenAI’s post says Promptfoo’s technology will allow its agent platform to perform automated red-teaming, evaluate agent workflows for security concerns, and monitor activities for risks and compliance requirements. The company also said it hopes to continue building out PromptFu’s open-source offering.
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