Server Side Public License

The Server Side Public License (SSPL) is a non-free strong copyleft software license first introduced by MongoDB Inc. in 2018.

It includes most of the text and provisions of the GNU Affero General Public License version 3 (AGPL v3), but requires anyone who offers the functionality of SSPL-licensed software to third-parties as a service to release the entirety of the service's source code, including all software, APIs, and other software that would be required for a user to run an instance of the service themselves, under the SSPL. This is in contrast to the AGPL, whose equivalent copyleft provision only applies to the source code of the licensed work itself, when conveyed over a network.

The SSPL is not recognized as free software by the Open Source Initiative (OSI), as the aforementioned provision is considered discriminatory against commercial users, and encumbers the use of software used together with an SSPL-licensed program.