ZeroTier’s software kit is licensed under the ZeroTier BSL, which allows source code access and free use for all with the exception of hosting a network controller for commercial purposes or embedding the ZeroTier source code in a commercial application. You can self-host ZeroTier controllers and nodes for free if you use it for non-commercial purposes. Please contact us to learn more.

ZeroTier’s BSL is based on the Business Source License (BSL) version 1.1 developed by MariaDB. This license has been adopted by other commercial open source projects like CockroachDB.

The BSL also carries an expiration date (“change date”) after which the licensed work reverts to a more permissive license of the author’s choice (Apache License 2.0 in our case). Each major release can carry an updated change date, allowing the author to extend the BSL’s coverage into the future for new releases. The existence of a change date means that should the original project’s author(s) abandon the project it will eventually fall into a more permissive open source license and can be taken over by the community.