PromptFoo started as an internal utility: a small set of tools we kept rebuilding across projects. It turned out the same problems — writing a prompt from scratch, tightening a rough one, comparing model costs — were problems every team had.

We publish the tools that work, write about the ones that don't, and organize a library of prompts you can actually use. No downloads. No API keys. Just a workshop.

Everything is designed to be fast, honest, and portable. If it doesn't earn its place, it doesn't ship.