Licensing

Cairn is open source under the GNU Affero General Public License v3.0 (AGPL-3.0). The full text is in LICENSE.

What this means for you

• Read, audit, run, and fork the code — freely.
• Self-host Cairn for your own use, internal or commercial. See Self-hosting.
• Modify it however you like.

The one obligation, which is the point of AGPL: if you run a modified version of Cairn as a network service, you must make your modified source available to the users of that service. Running Cairn unmodified, or using it internally, carries no such obligation beyond the license terms.

Why AGPL

AGPL keeps Cairn genuinely open source while preventing a closed-source competitor from taking the code, adding proprietary features, and reselling it as a service without contributing anything back. It's the same license used by projects like Documenso, Cal.com, PostHog, and Grafana.

Managed cloud & Enterprise

The open-source project is the full product. On top of it we offer:

• a managed cloud — the convenience of not running the infrastructure yourself; and
• an Enterprise edition — additional features for larger organizations.

This is the standard "open-core" model and is how the project sustains development. The core stays open under AGPL-3.0.

Contributing

So the project can keep offering the managed edition, opening a pull request means you agree to the Contributor License Agreement — you keep copyright and grant Cairn a broad license to use your contribution. See Contributing.

Trademarks

The Cairn name and logo are trademarks. The AGPL covers the code, not the brand — you can fork and run the code, but please don't represent your fork as official "Cairn".

Privacy & data

For how the hosted service handles data, see the Privacy Policy, Terms of Service, and DPA. Cairn never trains models on your private code.