promptfoo
promptfooDeclarative CLI and Node library that tests prompts, agents and RAG pipelines from a YAML config, comparing model outputs side by side and running the same assertions in CI. It also ships a red-teaming mode that scans an application for jailbreaks and other vulnerabilities, which most eval harnesses leave out.
Promptfoo became part of OpenAI and the project continues in the open. It is distributed npm-first, so the PyPI package is a minority channel and is deliberately not declared as an artifact. Verified 2026-08-13 via the promptfoo repository, its license endpoint and its README.
Openness
5 high confidence- license
- MIT(OSI)
- source
- public(GitHub)
- core-gated
- ungated
MIT-licensed and fully public, and MIT is an OSI license, so this is open source. OpenAI now owns the project, which does not change the license the code ships under.
- https://github.com/promptfoo/promptfoo recorded 2026-06-04
MIT license; 'remains open source and MIT licensed' under OpenAI; v0.121.14
- https://api.github.com/repos/promptfoo/promptfoo/license recorded 2026-08-13
GitHub's license endpoint reports spdx_id MIT for promptfoo/promptfoo and returns the MIT text as the LICENSE body.
- https://raw.githubusercontent.com/promptfoo/promptfoo/main/README.md recorded 2026-08-13
README states 'Promptfoo is now part of OpenAI. Promptfoo remains open source and MIT licensed' and lists 'Open source - MIT licensed, with an active community' among its properties. The CLI installs and runs from npm with no account, and nothing in the README offers a paid tier, an enterprise edition or a license key.
Adoption
4 high confidenceThe npm registry reports 2,277,977 downloads of promptfoo in the trailing month, inside the 1M-10M band, against 21.9k GitHub stars, and the project states it powers LLM apps serving more than 10M users in production. npm is the right channel to read because promptfoo is an npm-first CLI. A PyPI package named promptfoo also exists and is genuinely this project's, but it sees only 13,629 downloads a month; banding on that would substitute a minority channel for the product's real distribution and understate its reach by two rungs.
- https://api.npmjs.org/downloads/point/last-month/promptfoo recorded 2026-08-13
2,277,977 npm downloads for 2026-07-11 to 2026-08-09
- https://github.com/promptfoo/promptfoo recorded 2026-06-04
21.9k stars; '10M+ users in production' claim
- https://raw.githubusercontent.com/promptfoo/promptfoo/main/README.md recorded 2026-08-13
The repo carries 24.2k stars and the README positions the tool as used by OpenAI and Anthropic. No standalone user count is published beyond that.
Capability
4 high confidenceVery broad eval coverage plus a distinctive red-teaming and security axis. Top-tier for application evaluation, though below the academic-benchmark standardization references such as lm-evaluation-harness on raw benchmark coverage.
- https://github.com/promptfoo/promptfoo recorded 2026-06-04
eval + red-teaming + model comparison + CI/CD features
- https://raw.githubusercontent.com/promptfoo/promptfoo/main/README.md recorded 2026-08-13
README lists red teaming and vulnerability scanning, side-by-side model comparison across OpenAI/Anthropic/Azure/Bedrock/Ollama, CI/CD automation, and 'live reload and caching' - the same feature set the band was placed on.
Verified 2026-08-13