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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.

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Server Side Public License
AuthorMongoDB Inc.
PublishedOctober 16, 2018 (2018-10-16)
SPDX identifierSSPL-1.0
Debian FSG compatibleNo
FSF approvedNo
OSI approvedNo
GPL compatibleNo
CopyleftYes
Linking from code with a different licenseNo
Websitewww.mongodb.com/licensing/server-side-public-license

The Server Side Public License (SSPL) is a non-free strong copyleft software license first introduced by MongoDB Inc. in 2018.12

It includes most of the text and provisions of the GNU Affero General Public License version 3 (AGPL v3),3 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.

License terms

The SSPL is based on the GNU Affero General Public License (AGPL), with a modified Section 13 which requires those making SSPL-licensed software available to third-parties (modified or not) as part of a "service" to release the source code for the entirety of the service, including without limitation all "management software, user interfaces, application program interfaces, automation software, monitoring software, backup software, storage software and hosting software, all such that a user could run an instance of the service using the Service Source Code you make available", under the SSPL.3 The chapter structure of the Server Side Public License is identical to that to the AGPL, except that the GPL preamble and application instructions are stripped from the license text.3

MongoDB Inc. stated that Section 13 in the AGPL (which requires that those using the AGPL-licensed software over a network have the ability to obtain the source code for the software, as used) had an unclear scope, and that the SSPL's version "clearly and explicitly sets forth the conditions to offering the licensed program as a third-party service".245

Licensed software

In October 2018, the MongoDB database was relicensed under the SSPL. Debian, Red Hat Enterprise Linux, and Fedora subsequently dropped MongoDB, citing concerns about the SSPL. Amazon released a partially compatible but proprietary service named DocumentDB.67

In November 2020, Graylog announced that version 4.0 of its source-available release will be licensed under the SSPL.8

In January 2021, Elastic NV announced that future versions of their code in Elasticsearch and Kibana, licensed until then under the open-source Apache License 2.0, would be dual-licensed instead under SSPL and their own Elastic license.9 Critics of the re-licensing decision predicted that it would harm Elastic's ecosystem, and Amazon responded with plans to fork the projects for continued development of versions licensed under the Apache License.10 Other users of the Elasticsearch ecosystem, led by Amazon Web Services, and including Logz.io, CrateDB, Red Hat and Aiven, also collaborated on the open source fork, leading to the creation of the OpenSearch software.11121314

Redis moved away from the three-clause BSD license on March 20, 2024.15 Users now have a choice between the SSPLv1 license and their own Redis Source Available License (RSALv2). This change in licensing upset many users, prompting The Linux Foundation to create a fork called Valkey, using Redis' final BSD-licensed iteration as a base.16 On May 1, 2025, Redis announced it was releasing Redis 8 under the open source AGPLv3 license. Some developers argued the change did not go far enough to making the software freely available for all.17

Certification with OSI

In 2018, MongoDB submitted the license to the Open Source Initiative (OSI) for approval. The company withdrew its submission in 2019.1819 Bruce Perens stated that the license specifically violates sections 6 and 9 of The Open Source Definition, as it discriminates against commercial use of licensed software as part of a service,20 and "encumber[s] entirely separate programs which are simply used together with the licensed program."21 In 2021, the OSI described the SSPL and similar licenses as a "fauxpen" source license.22

References

References

  1. "Server Side Public License (SSPL)". MongoDB. Retrieved January 14, 2021.
  2. "Server Side Public License FAQ". MongoDB. Retrieved April 27, 2021.
  3. Ward, Sarah. "SSPL compare to AGPL" (PDF).
  4. Baer, Tony. "It's MongoDB's turn to change its open source license". ZDNet. Archived from the original on October 31, 2018. Retrieved October 16, 2018.
  5. "MongoDB switches up its open source license". TechCrunch. Archived from the original on October 16, 2018. Retrieved October 16, 2018.
  6. Vaughan-Nichols, Steven J. "MongoDB "open-source" Server Side Public License rejected". ZDNet. Retrieved January 14, 2021.
  7. "#915537 - MongoDB SSPL v1 license and the DFSG - Debian Bug report logs". bugs.debian.org. Retrieved January 14, 2021.
  8. "Graylog v4.0 Licensing SSPL | Graylog". www.graylog.org. Retrieved January 14, 2021.
  9. "Doubling down on open, Part II". Elastic Blog. January 14, 2021. Retrieved January 15, 2021.
  10. Krazit, Tom (January 21, 2021). "'It's not OK': Elastic takes aim at AWS, at the risk of major collateral damage". Protocol — The people, power and politics of tech. Archived from the original on January 7, 2022. Retrieved January 22, 2021.
  11. Vaughan-Nichols, Steven J. "AWS, as predicted, is forking Elasticsearch". ZDNet. Retrieved January 28, 2021.
  12. "CrateDB Doubling Down on Permissive Licensing and the Elasticsearch Lockdown". CrateDB. January 27, 2021. Retrieved January 28, 2021.
  13. "Momentum Builds to Break Elasticsearch Licensing Deadlock". Datanami. January 25, 2021. Retrieved January 31, 2021.
  14. Vaughan-Nichols, Steven (April 13, 2021). "OpenSearch: AWS rolls out its open source Elasticsearch fork". TechRepublic. Retrieved September 3, 2021.
  15. Trollope, Rowan (March 20, 2024). "Redis Adopts Dual Source-Available Licensing". Redis. Retrieved March 29, 2024.
  16. "Linux Foundation Launches Open Source Valkey Community". www.linuxfoundation.org. Retrieved March 29, 2024.
  17. Clark, Lindsay. "Redis 'returns' to open source with AGPL license". The Register. Retrieved July 2, 2025.
  18. Horowitz, Eliot. "[Email thread reply] Approval: Server Side Public License, Version 2 (SSPL v2)". Retrieved January 23, 2021.
  19. Gall, Richard (March 12, 2019). "MongoDB withdraws controversial Server Side Public License from the Open Source Initiative's approval process". Packt Hub. Retrieved January 14, 2021.
  20. Perens, Bruce (February 17, 2019). "[License-review] Approval: Server Side Public License, Version 2 (SSPL v2)". License Review Mailing List of the Open Source Initiative (Mailing list). Open Source Initiative. Archived from the original on April 11, 2023. Retrieved March 29, 2024. Section 13 is very obviously intended to be a restriction against the field of endeavor of offering the software as a service, and thus not in compliance with OSD #6.
  21. Perens, Bruce (February 17, 2019). "[License-review] Approval: Server Side Public License, Version 2 (SSPL v2)". License Review Mailing List of the Open Source Initiative (Mailing list). Open Source Initiative. Archived from the original on April 11, 2023. Retrieved March 29, 2024. it doesn't appear that you've addressed the main problem with the license, which is that it attempts to encumber entirely separate programs which are simply used together with the licensed program.
  22. OSI Board of Directors (January 19, 2021). "The SSPL is Not an Open Source License". Open Source Initiative. Archived from the original on December 4, 2022. Retrieved February 19, 2023.
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