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OpenAI Acquires Promptfoo to Secure Its AI Agents
The deal underscores how frontier labs are scrambling to prove their technology can be used safely in critical business operations.
Mar. 9, 2026 at 5:49pm by Ben Kaplan
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OpenAI announced it has acquired Promptfoo, an AI security startup founded in 2024 to protect large language models (LLMs) from online adversaries. The frontier lab said Promptfoo's technology will be integrated into OpenAI Frontier, its enterprise platform for AI agents, to allow for automated red-teaming, security evaluation of agentic workflows, and risk and compliance monitoring.
Why it matters
The development of independent AI agents that perform digital tasks has generated excitement about productivity gains, but also given bad actors fresh opportunities to access sensitive data or manipulate automated systems. This deal highlights the growing need for robust security measures as frontier labs work to deploy their AI technology safely in critical business operations.
The details
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 its products are used by more than 25% of Fortune 500 companies. Promptfoo has raised $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 announced the acquisition on March 9, 2026.
- Promptfoo was founded in 2024.
The players
OpenAI
An artificial intelligence research company that develops large language models and other AI technologies.
Promptfoo
An AI security startup founded in 2024 to protect large language models from online adversaries.
Ian Webster
Co-founder of Promptfoo.
Michael D'Angelo
Co-founder of Promptfoo.
The takeaway
This acquisition highlights the growing importance of robust security measures as frontier labs like OpenAI work to deploy their AI technology safely in critical business operations, amid concerns about bad actors exploiting vulnerabilities in independent AI agents.
