The Free Software Foundation published this copyleft license on 19 November 2007 as part of the GNU Project. It is the General Public License (GPL) version 3 with one extra duty: if you modify the program and let people interact with it over a network, you must offer them the corresponding source of that modified version.
GNU GPL version 3 (GPL) still treats mere interaction through a computer network, with no transfer of a copy, as not conveying. A vendor can therefore run a modified GPL program as a public Software as a Service (SaaS) product and keep the fork closed. The FSF wrote this Affero edition to close that SaaS loophole for modified versions. An earlier Affero General Public License from Affero, Inc. had the same aim; the FSF’s text is a different license, based on GPL-3, not a numbered revision of Affero’s document. SPDX identifies this exact choice as AGPL-3.0-only, as distinct from an AGPL-3.0-or later notice that also accepts future FSF versions.
Section 13 and the Network Copyleft
Section 13 is titled Remote Network Interaction; Use with the GNU General Public License. The extra rule sits on top of the GPL-3 conveying rules rather than redefining them:
- Modification trigger: The extra source offer applies when you modify the Program. Hosting an unmodified copy does not, by itself, create that section 13 duty.
- Remote users: The modified version must prominently offer every user who interacts with it remotely through a computer network a chance to receive the Corresponding Source, at no charge, from a network server, by ordinary means of copying software.
- What counts as interaction: The FSF’s FAQ treats programs designed to accept requests and send responses over a network (web and mail servers, interactive web applications, online game servers) as in scope. Running a program over SSH or a remote X session, when the program was not designed for that, does not.
- Combination with GPL-3: Both licenses allow you to link or combine AGPL-3.0-covered work with GPL-covered work. The Affero terms continue to apply to the Affero part; the GPL-3 part stays under GPL-3.
- Internal copies: Making and running copies inside one organization is not distribution. The extra network rule still depends on remote users interacting with a modified version.
GitHub’s Choose a License catalog treats this as a strongest-copyleft license because a modified version used to provide a network service must make complete source available. The same catalog lists commercial use, modification, distribution, patent use, and private use as permissions, conditioned on preserving copyright and license notices, stating changes, disclosing source, and relicensing the covered work under the same terms. Warranty and liability are disclaimed. The FSF text does not call network use distribution: it keeps interaction without a copy outside conveying, then adds section 13 on top.
Compared with GPL-3.0 and GPL-2.0
The ordinary GPL family still keys copyleft to distribution (GPL) or conveying a copy (GPL-3.0). This Affero edition adds the network trigger on top of the GPL-3 base, including GPL-3’s express patent license and its limits on treating the work as an effective digital rights management (DRM) measure.
| Topic | AGPL-3.0 | GPL | GPL |
| Publisher | Free Software Foundation | Free Software Foundation | Free Software Foundation |
| Date | 19 November 2007 | 29 June 2007 | June 1991 |
| Copyleft trigger | Conveying a copy, plus remote use of a modified version | Conveying a copy | Distributing a copy |
| Network / SaaS | Modified version must offer Corresponding Source to remote users | Hosting a modified server does not, by itself, require source | No network copyleft |
| Patent license | Express grant (GPL-3 text) | Express grant | No express patent license |
| Devices / circumvention | Anti-circumvention and installation information for user products | Same as AGPL-3.0 | Not in GPL-2 |
| Combine with AGPL-3.0 | This text | Permitted (section 13 in both licenses) | Incompatible with GPL-3 and AGPL-3 |
Hosted Software and Commercial Avoidance
Companies that sell hosted software often refuse AGPL dependencies because a private patch on a public service can force a source release, and because combining the library with a proprietary stack is treated as a viral risk. Procurement teams used to negotiating an end-user license agreement (EULA) also hit section 10: you may not add further restrictions. Some Open Source Software (OSS) vendors dual-license a community Affero edition beside a paid proprietary grant so customers who will not disclose modifications buy out of copyleft.
Google’s published AGPL policy is blunt: “Code licensed under the GNU Affero General Public License (AGPL) MUST NOT be used at Google.” The company cites the difficulty of complying with network copyleft on remotely accessed products such as Search, Gmail, Maps, and YouTube, and the risk that an accidental dependency would require publishing corresponding source for the service.
- Grafana: Grafana Labs relicensed Grafana, Grafana Loki, and Grafana Tempo from the Apache License 2.0 (Apache-2.0) to AGPLv3 in April 2021. Plugins, agents, and some libraries stayed under Apache.
- Nextcloud: Nextcloud and Nextcloud Enterprise are licensed under GNU AGPLv3. Nextcloud’s FAQ states that unmodified use (including configuration) does not require publishing source, while code modifications must be made available under AGPLv3 or a compatible license to system users.
- MongoDB: MongoDB Community Server was licensed under GNU AGPLv3. Releases and patches on or after 16 October 2018 use MongoDB’s Server Side Public License (SSPL). MongoDB’s FAQ states that the Open Source Initiative has not approved the SSPL. SSPL’s rewritten section 13 is broader than AGPL’s: offering the program as a service requires publishing Service Source Code, including management software, user interfaces, APIs, automation, monitoring, backup, storage, and hosting software sufficient to run an instance of the service.
Free and Open Source Software (FOSS) catalogs still treat GNU AGPLv3 as a free, copyleft license. SSPL is a different instrument, written because MongoDB believed cloud vendors were testing AGPL’s boundaries. Teams that host modified AGPL code for customers should budget for a source-offer mechanism (the FSF’s own example is a Source link on a web application) and should not assume a thin API wrapper defeats section 13.