OpenAI acquires Promptfoo to secure its AI assistants

OpenAI announced on Monday that it has acquired Promptfoo, an AI security system launched in 2024 to protect LLMs from cyber attackers.

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

The growth of independent AI assistants working on digital services has led to excitement about the benefits. But they also give criminals new opportunities to access sensitive data or modify systems. This underscores how frontier laboratories are scrambling to ensure that their technology can be safely applied to complex business applications.

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

Promptfoo has raised just over $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 price of the transaction.

OpenAI notes that Promptfoo’s technology will allow its platform to create a red team, analyze workflows for security issues, and analyze potential threats and compliance requirements. The company also said it hopes to continue to make open source offerings for Promptfoo.