Promptfoo, an open-source framework for AI red-teaming and security testing, has announced $18.4 million in Series A financing led by Insight Partners, with participation from Andreessen Horowitz.
Founded in 2024, Promptfoo is establishing itself as a standard for AI security testing, with over 100,000 developers and more than 30 Fortune 500 companies utilizing its tools. The platform helps developers secure large language models (LLMs) and generative AI applications by addressing risks like prompt injection, data leakage, and insecure tool usage. Its commercial solution, launched last year, is trusted by major retailers, telecoms, and financial institutions.
As enterprise AI adoption accelerates, Promptfoo’s platform stands out by integrating automated red-team tests into the build and release process. This end-to-end automation streamlines workflows for security and engineering teams, making it a top choice for organizations deploying AI securely.
How the funding will be used: The new funding will enable Promptfoo to expand its team and enhance platform development, addressing the growing demand from Global 2000 companies for comprehensive AI security solutions.
KEY QUOTES:
“AI security has become the largest blocker to enterprises shipping generative AI applications to end users. Architectures like RAG, agents, and most recently MCP have expanded what’s possible with AI, but they’ve dramatically increased the attack surface.”
Ian Webster, CEO and co-founder of Promptfoo
“Promptfoo has created what we believe to be a category-defining product. The layers of The Next Stack built around AI are clearly emerging beyond LLMs, and Promptfoo is a critical part of that evolution—especially in the race to enable intelligence-first design and secure Enterprise AI. Serious enterprises deploying AI will need comprehensive security testing, and Promptfoo’s combination of technical depth, open source adoption, and enterprise traction positions them perfectly to capture this massive market opportunity. We’re thrilled to partner with them as they help build the full AI security suite.”
Ganesh Bell, Managing Director at Insight Partners
“When we first invested in Promptfoo, we recognized that AI security would become mission-critical for every enterprise. In just one year, they’ve validated that thesis and then some. This additional investment reflects our conviction that they’ll define how companies approach AI security for years to come.”
Zane Lackey, General Partner at Andreessen Horowitz
