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License

Short version:

  • The Mercure protocol is open. Anyone can implement it, including in proprietary software.

  • The Mercure.rocks Hub is licensed under AGPL-3.0. Modifications to the hub itself must be shared.

  • Software that uses the hub (publishers, subscribers, your application) is not affected by the AGPL. Use any license you want: proprietary, MIT, GPL, anything.

  • For organizations that can't use AGPL software, commercial licenses are available.

The Mercure protocol license

The Mercure specification is published under the IETF copyright policy. It can be implemented by any software, including proprietary software, with no royalty or attribution requirement.

The Mercure.rocks reference hub license

The Mercure.rocks Hub (this repository) is AGPL-3.0.

In practice:

  • Running the hub. No restriction on who runs it or for what purpose.

  • Modifying the hub. Your modifications must be made available under AGPL-3.0 to anyone you give the modified version to: including users who interact with it over a network.

  • Publishers and subscribers. Software that talks to the hub over the protocol does not become AGPL. The AGPL is about the hub binary itself, not anything that connects to it. A proprietary backend that publishes to a Mercure hub stays proprietary.

This is the same shape of license as MongoDB Community pre-SSPL: it lets anyone use the hub freely while preventing third parties from running modified versions as a proprietary SaaS without contributing back.

Commercial licenses

If your organization can't use AGPL-3.0 (some compliance teams refuse it categorically), commercial licenses are available:

  • Self-Hosted Mercure: comes with a commercial license to the binary, plus the multi-node transports and direct support. Pricing starts at €1,500/year.

  • Custom licensing for cases that don't fit either option: contact@mercure.rocks.

The commercial license is grant-based and doesn't require contributing modifications back. Your legal team can review the terms before purchase.

Mercure trademarks

"Mercure" and "Mercure.rocks" are trademarks of Dunglas Services SAS. The trademarks are not licensed under the AGPL: you can't use them in the name of your own product without permission. Implementations that pass the conformance tests may describe themselves as "compatible with the Mercure protocol."

Contributing to the Mercure.rocks hub

Contributions are welcome under AGPL-3.0. By submitting a pull request you agree to license your contribution under the same terms as the rest of the project. See CONTRIBUTING.md for the development workflow.

Mercure patent grant

The AGPL-3.0 includes an explicit patent grant from contributors. The protocol itself, published as an IETF Internet-Draft, is subject to the IETF's patent policy.

Mercure licensing questions

For licensing questions that aren't answered here, email contact@mercure.rocks.