Benchmarks & Deep Dives · Freemium

Promptfoo

Promptfoo is an MIT-licensed open-source CLI and library for evaluating and red-teaming LLM applications. Tests are defined in a promptfooconfig.yaml file with prompts, providers and assertions, ranging from deterministic checks like contains, regex and is-json to model-graded rubrics, and results can be compared side by side in a local web viewer or run in CI. The Community version is free; Enterprise and on-premise plans add team features and support. OpenAI announced in March 2026 that it would acquire Promptfoo, which remains open source.