head to head · open source
langchain vs promptfoo
langchain has 148,892 GitHub stars, 25,031 forks, 492 open issues and last shipped yesterday. promptfoo has 26,753 stars, 2,633 forks, 651 open issues and last shipped yesterday. langchain leads on adoption by 457% (148,892 vs 26,753 stars). langchain is written in Python under MIT; promptfoo is written in TypeScript under MIT. langchain has attracted 17% as many forks as stars, promptfoo 10%. promptfoo was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| langchain | promptfoo | |
|---|---|---|
| GitHub stars | ★ 149K | ★ 27K |
| License | MIT | MIT |
| Written in | Python | TypeScript |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 25K | ⑂ 2.6K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick langchain if
- You weight community size — 149K stars and counting
- You want the MIT license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick promptfoo if
- You want the promptfoo feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches TypeScript
- You evaluated both and promptfoo fits your workflow better
About langchain
The agent engineering platform. LangChain is a framework for building agents and LLM powered applications. It helps you chain together interoperable components and third party integrations to simplify AI application development — all while future proofing decisions as the underlying technology evolves. [!TIP] Just getting started? Check out Deep Agents — a higher level package built on LangChain for agents that have built in capabilities for common usage patterns such as planning, subagents, file system usage, and more. Quickstart If you're looking for more advanced customization or agent orchestration, check…
read the full langchain overview →
About promptfoo
Promptfoo: LLM evals & red teaming promptfoo is a CLI and library for evaluating and red teaming LLM apps. Stop the trial and error approach start shipping secure, reliable AI apps. Website · Getting Started · Red Teaming · Documentation · Discord Promptfoo is now part of OpenAI. Promptfoo remains open source and MIT licensed. Read the company update. Quick Start Requires Node.js =22.22.0 for npm and npx usage. Node.js 24 LTS is recommended; see the runtime support guide. Also available via brew install promptfoo and pip install promptfoo . You can also use npx promptfoo@latest to run any command without…
read the full promptfoo overview →
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Frequently asked questions
Is langchain or promptfoo more popular?
langchain has 148,892 GitHub stars and promptfoo has 26,753. langchain has the larger community by that measure.
Are langchain and promptfoo free?
Both are open source. langchain is licensed under MIT and promptfoo under MIT. Neither carries a licence fee.
What is the difference between langchain and promptfoo?
langchain is written in Python and promptfoo in TypeScript. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, langchain or promptfoo?
Choose langchain if you want the larger community (148,892 stars) or its MIT licence terms. Choose promptfoo if its feature set, stack or MIT licence fits better. Both are self-hostable.