Promptfoo Resources
Prompt engineering tutorials, evaluation guides, and developer resources for the AI era.
Looking for promptfoo? Here's what you need to know.
Promptfoo (also written prompt foo or prompt-foo) is an open-source framework for AI prompt testing and LLM evaluation — not affiliated with this site.PromptFu (promptfu.dev) is an independent prompt engineering resource covering testing frameworks, evaluation strategies, CLI tools, and best practices across all AI providers.
Following OpenAI's acquisition of promptfoo.dev in March 2026, we've published several articles covering the framework and what the acquisition means for the prompt engineering community. Browse our coverage below, alongside our broader library of prompt engineering resources.
PromptFu vs promptfoo — the key distinction
These are related but different things. Here's how they fit together.
The open-source CLI and Node.js library for testing and evaluating LLM prompts. You install it, write test cases in YAML, and run promptfoo eval to grade your prompts automatically.
Originally at promptfoo.dev. Now acquired by OpenAI (March 2026).
An independent knowledge hub for prompt engineers and AI developers. We publish tutorials, cheat sheets, framework comparisons, and LLM evaluation guides — all vendor-neutral and community-driven.
Lives at promptfu.com. Run independently since 2024.
Essential Promptfoo Resources
New to promptfoo? Start here. Learn what it is, how it works, and how to write your first test suite for LLM prompts.
Read the guideThe complete promptfoo CLI reference. Commands, flags, configuration options, and example YAML test cases all in one place.
View cheat sheetWhat does OpenAI's acquisition of promptfoo mean for the community, the tool, and independent prompt engineers?
What it meansAbout This Site
PromptFu (promptfu.com) is an independent publication covering AI prompt engineering, LLM evaluation, and developer tools for the AI era. We are not affiliated with OpenAI or the promptfoo project maintainers. Our content is vendor-neutral.
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