Sam Altman, CEO of OpenAI Inc., attends the AI Impact Summit on Thursday, February 19, 2026 in New Delhi, India.
Prakash Singh | Bloomberg | Getty Images
OpenAI announced Monday that it will acquire cybersecurity startup Promptfoo, which provides tools to help protect and test complex artificial intelligence systems.
The company, led by Sam Altman, did not disclose the terms of the deal, but said Promptfu’s team would join OpenAI. Promptfoo’s security tools will be built within OpenAI’s Frontier platform for AI agents.
“As AI agents become more connected to real-world data and systems, securing and verifying them becomes more difficult and important than ever,” Promptfoo CEO Ian Webster said in a statement. “By joining OpenAI, we can accelerate this effort and bring stronger security, safety, and governance capabilities to teams building real-world AI systems.”
OpenAI also helps developers test various AI-related prompts and agents, including GPT, Anthropic’s Claude, googleGemini.
Promptfoo announced in July that it had raised $18.4 million in Series A funding led by Insight Partners with participation from Andreessen Horowitz.
The startup has 11 employees and has raised a total of $22.68 million as of July 2025, with an ex-post valuation of $85.5 million, according to deal tracking service PitchBook.
Andreessen Horowitz has been expanding into infrastructure and defense markets, most recently announcing in January that it had raised $15 billion as part of its American Dynamism fundraising efforts.
From the proceeds, $6.75 billion will be allocated to a growth fund, while two other $1.7 billion funds will each focus on apps and infrastructure, the venture capital firm said.
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