Server Side Public License
|Debian FSG compatible||No|
|GPL compatible||No|
The Server Side Public License (SSPL) is a very strong copyleft source-available open core software license introduced by MongoDB Inc. in 2018. It is a modified version of the GNU Affero General Public License version 3 (AGPL v3), which mandates that anyone that offers the functionality of the SSPL-licensed software to third-parties as a service, must release the entirety of their 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.
While the company maintains that it grants "all of the same freedoms the community has always had with MongoDB under [the GNU Affero General Public License]", the SSPL is not recognized as free software by multiple parties, including the Open Source Initiative (OSI) and multiple major Linux distributions, as the aforementioned provision is discriminatory towards specific fields of use.
The SSPL is based on the GNU Affero General Public License, with a modified Section 13 that requires that those making SSPL-licensed software available to third-parties (modified or not) as part of a "service" must 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. The chapter structure of the Server Side Public License is identical to that of Affero GPL's, except that the GPL preamble and application instructions are stripped from the license text.
MongoDB Inc. stated that the license was based on GPL v3 because a similar clause for network software in the GNU Affero General Public License 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".
In October 2018, the MongoDB database was relicensed under the SSPL. The Debian, Red Hat Enterprise Linux, and Fedora Linux distributions subsequently dropped MongoDB, citing concerns about the SSPL. Amazon released a partially compatible but proprietary service named DocumentDB.
In January 2021, Elastic NV announced that future versions of their code in Elasticsearch and Kibana, licensed until then under the open-source Apache 2.0 License, would be dual-licensed instead under SSPL and their own Elastic license. 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 as Apache 2.0. Other users of the Elasticsearch ecosystem, including Logz.io, CrateDB, Red Hat and Aiven, also collaborated on the open source fork, leading to the creation of the OpenSearch software.
Certification with OSI
In 2018, MongoDB submitted the license to the Open Source Initiative (OSI) for approval. The company withdrew its submission in 2019. In January 2021, following the re-licensing move by Elastic, OSI released a statement declaring that the SSPL does not comply with its Open Source Definition because it discriminates against specific fields of endeavor, describing it as a "fauxpen" source license.
- "Server Side Public License (SSPL)". MongoDB. Retrieved January 14, 2021.
- "Server Side Public License FAQ". MongoDB. Retrieved April 27, 2021.
- Ward, Sarah. "SSPL compare to AGPL" (PDF).
- OSI Board of Directors (January 19, 2021). "The SSPL is Not an Open Source License". Open Source Initiative. Retrieved January 23, 2021.
- 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.
- "MongoDB switches up its open source license". TechCrunch. Archived from the original on October 16, 2018. Retrieved October 16, 2018.
- Vaughan-Nichols, Steven J. "MongoDB "open-source" Server Side Public License rejected". ZDNet. Retrieved January 14, 2021.
- "#915537 - MongoDB SSPL v1 license and the DFSG - Debian Bug report logs". bugs.debian.org. Retrieved January 14, 2021.
- "Graylog v4.0 Licensing SSPL | Graylog". www.graylog.org. Retrieved January 14, 2021.
- "Doubling down on open, Part II". Elastic Blog. January 14, 2021. Retrieved January 15, 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. January 21, 2021. Retrieved January 22, 2021.
- Vaughan-Nichols, Steven J. "AWS, as predicted, is forking Elasticsearch". ZDNet. Retrieved January 28, 2021.
- "CrateDB Doubling Down on Permissive Licensing and the Elasticsearch Lockdown". CrateDB. January 27, 2021. Retrieved January 28, 2021.
- "Momentum Builds to Break Elasticsearch Licensing Deadlock". Datanami. January 25, 2021. Retrieved January 31, 2021.
- Vaughan-Nichols, Steven (April 13, 2021). "OpenSearch: AWS rolls out its open source Elasticsearch fork". TechRepublic. Retrieved September 3, 2021.
- Horowitz, Eliot. "[Email thread reply] Approval: Server Side Public License, Version 2 (SSPL v2)". Retrieved January 23, 2021.
- 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.