head to head · open source
langchain vs loopy
langchain has 148,892 GitHub stars, 25,031 forks, 492 open issues and last shipped yesterday. loopy has 3,216 stars, 285 forks, 5 open issues and last shipped 2 months ago. langchain leads on adoption by 4,530% (148,892 vs 3,216 stars). langchain is written in Python under MIT; loopy is written in JavaScript under MIT. langchain has attracted 17% as many forks as stars, loopy 9%. langchain was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (ai-agents), so they are genuine substitutes rather than adjacent tools.
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 | loopy | |
|---|---|---|
| GitHub stars | ★ 149K | ★ 3.2K |
| License | MIT | MIT |
| Written in | Python | JavaScript |
| Last push | 2026-11-02 | 2026-09-11 |
| Forks | ⑂ 25K | ⑂ 285 |
| 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 loopy if
- You want the loopy feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches JavaScript
- You evaluated both and loopy 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 loopy
Loop Library Loop Library has two separate but related parts in this repository: The website is the library; Loopy is a companion way to work with it. You can browse or give an agent the website without installing Loopy. Installing Loopy adds the guided workflow, but it does not install or host the website. Agents that do not have Loopy can use the published agent guide, agent instructions, JSON catalog, or plain text catalog directly. Each published loop tells an agent what to do, how to check its work, what to try next, and when to stop. What is a loop? Most prompts ask an agent to do something once. A loop…
read the full loopy overview →
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Frequently asked questions
Is langchain or loopy more popular?
langchain has 148,892 GitHub stars and loopy has 3,216. langchain has the larger community by that measure.
Are langchain and loopy free?
Both are open source. langchain is licensed under MIT and loopy under MIT. Neither carries a licence fee.
What is the difference between langchain and loopy?
langchain is written in Python and loopy in JavaScript. 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 loopy?
Choose langchain if you want the larger community (148,892 stars) or its MIT licence terms. Choose loopy if its feature set, stack or MIT licence fits better. Both are self-hostable.