The GNU Affero General Public License 3.0 (AGPL-3.0) is a copyleft open-source license designed to protect users’ freedom and ensure that the source code of a web application is accessible to users even when the application is accessed over a network. This license is a variant of the GNU General Public License 3.0 (GPL-3.0), with an added clause to address the specific challenges posed by web-based services.

Key Features of AGPL-3.0:

  1. Copyleft Provision:
    Like the GPL-3.0, the AGPL-3.0 incorporates a strong copyleft provision. It means that any software derived from or based on AGPL-3.0-licensed code must also be licensed under the AGPL-3.0. This ensures that the source code remains freely available and that any improvements or modifications made to the software are shared with the community.
  2. Network Interaction:
    The unique feature of the AGPL-3.0 is its extension of the copyleft requirements to software accessed over a network. In traditional GPL licenses, if a user modifies GPL-licensed software and runs it on a server, they are not obligated to share the modified source code with users who interact with the software over the network. The AGPL-3.0 closes this “ASP loophole” by mandating that users interacting with the software over a network have access to the corresponding source code.
  3. Obligations for Web Applications:
    When a user accesses a web application that is licensed under AGPL-3.0, the license requires the service provider to provide the complete source code of the application to the user. This includes any modifications or customizations made to the original AGPL-3.0-licensed software.
  4. Distribution of Source Code:
    The AGPL-3.0 specifies that if the web application’s source code is modified and distributed to users, it must be made available to those users under the same AGPL-3.0 license. This ensures that the principles of openness and transparency extend to all users, regardless of whether they interact with the application over a network or access it through a distributed version.
  5. Compatibility with GPL-3.0:
    One of the significant advantages of the AGPL-3.0 is its compatibility with the GPL-3.0. Code licensed under the AGPL-3.0 can be combined with code licensed under the GPL-3.0. However, it is essential to understand that if AGPL-3.0-licensed code is combined with GPL-3.0-licensed code, the entire combined work must be distributed under the terms of the AGPL-3.0.

Uses and Considerations:

The AGPL-3.0 is particularly well-suited for web applications, software as a service (SaaS), and cloud-based services. If you are developing a web application that you want to keep open source and ensure that users have access to the source code when using the application over a network, the AGPL-3.0 is a suitable choice.

However, developers and organizations need to be aware of the AGPL-3.0’s implications. Since the license requires sharing the source code even for web-based applications, some companies might be hesitant to use AGPL-3.0-licensed software in their proprietary services. Additionally, users who run AGPL-3.0-licensed software on their servers need to be diligent in providing access to the corresponding source code when serving the application over a network.


The AGPL-3.0 is a powerful open-source license that promotes the principles of software freedom and transparency for web applications and services. By ensuring users’ access to the source code of web-based software, the AGPL-3.0 helps maintain a vibrant and collaborative open-source community. Developers considering using or contributing to AGPL-3.0-licensed projects should be aware of its copyleft provisions and the responsibility to provide corresponding source code when offering services over a network. With its focus on network interaction and the distribution of source code, the AGPL-3.0 remains a key player in fostering openness and innovation within the digital landscape.

If you’re interested in exploring a comprehensive list of various open-source licenses and their details, feel free to check out our guide to “Open Source Licenses : A Guide To Software Licensing“. Happy licensing!

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