License and Copyright
tl;dr:
proprietary software can implement the Mercure specification
proprietary publishers and subscribers can be used with the Mercure.rocks Hub without having to share their sources
modifications made to the Mercure.rocks Hub must be shared
alternatively, commercial licenses are available for the Mercure.rocks Hub
The specification is available under the IETF copyright policy. The Mercure specification can be implemented by any software, including proprietary software.
The Mercure.rocks Hub is licensed under AGPL-3.0. This license implies that if you modify the Mercure.rocks Hub, you must share those modifications. However, the AGPL-3.0 license applies only to the hub server itself, not to software using this hub.
For companies not wanting, or not able to use AGPL-3.0 licensed software, commercial licenses are also available. Contact us for more information.