head to head · open source
langchain vs Cairn
langchain has 148,892 GitHub stars, 25,031 forks, 492 open issues and last shipped yesterday. Cairn has 4,757 stars, 922 forks, 10 open issues and last shipped 2 months ago. langchain leads on adoption by 3,030% (148,892 vs 4,757 stars). langchain is written in Python under MIT; Cairn is written in Python under AGPL-3.0. langchain has attracted 17% as many forks as stars, Cairn 19%. 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), 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 | Cairn | |
|---|---|---|
| GitHub stars | ★ 149K | ★ 4.8K |
| License | MIT | AGPL-3.0 |
| Written in | Python | Python |
| Last push | 2026-11-02 | 2026-09-07 |
| Forks | ⑂ 25K | ⑂ 922 |
| 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 Cairn if
- You want the Cairn feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches Python
- You evaluated both and Cairn 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 Cairn
Cairn More Than Just AI Penetration Testing — Towards General State Space Search Cairn is a general purpose problem solving engine. It defines no roles, no workflows. Given an origin and a goal, it searches for a path through an unknown state space. AI Penetration Testing is one such problem — and a proven one. What is Cairn? Penetration testing is fundamentally a directed search through a near infinite state space : Origin : known (target IP, target system) Goal : defined (get a shell, capture the flag) Path : unknown This structure is not unique to penetration testing. Vulnerability research, mathematical…
read the full Cairn overview →
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Frequently asked questions
Is langchain or Cairn more popular?
langchain has 148,892 GitHub stars and Cairn has 4,757. langchain has the larger community by that measure.
Are langchain and Cairn free?
Both are open source. langchain is licensed under MIT and Cairn under AGPL-3.0. Neither carries a licence fee.
What is the difference between langchain and Cairn?
langchain is written in Python and Cairn in Python. 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 Cairn?
Choose langchain if you want the larger community (148,892 stars) or its MIT licence terms. Choose Cairn if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.