companies

Promptfoo

Makes the open-source CLI developers use to test prompts, red-team LLM apps for jailbreaks and injection, and catch quality regressions before shipping.

In inglese

Ian Webster and Michael D'Angelo started Promptfoo in 2024 after Webster ran into a recurring problem building LLM features at Discord: prompts that worked fine in a demo would quietly break in production, with no good way to test them systematically. Promptfoo began as a command-line tool for running the same set of test cases against different prompts or models side by side, closer to a testing framework than a dashboard. The project's red-teaming features, which scan applications for jailbreaks, prompt injection, PII leakage, and other vulnerabilities using dozens of built-in attack techniques, turned it into one of the more widely used AI security tools; by early 2026 it counted more than 300,000 developers and adoption at over a quarter of the Fortune 500, including internal use at OpenAI and Anthropic. The project stayed MIT-licensed throughout. In March 2026, OpenAI announced it was acquiring Promptfoo to fold its testing and red-teaming technology into OpenAI's own agent products, while committing to keep the tool open source and continue supporting existing customers.

Founded

2024

Headquarters

San Francisco, United States

Sector

infrastructure