AGPL vs. GPL

Attribute	AGPL	GPL
License Type	Affero General Public License	General Public License
Scope	Extends GPL to cover use over a network	Does not cover use over a network
Derived Works	Requires derivative works to be licensed under AGPL	Requires derivative works to be licensed under GPL
Network Use	Requires source code availability for network users	Does not require source code availability for network users
Commercial Use	Allows commercial use	Allows commercial use

Introduction

When it comes to open-source licenses, two of the most popular choices are the GNU Affero General Public License (AGPL) and the GNU General Public License (GPL). Both licenses are designed to promote the sharing and collaboration of software code, but they have some key differences that developers and organizations need to consider when choosing which license to use for their projects.

Scope of Application

One of the main differences between AGPL and GPL is the scope of their application. The GPL is primarily focused on protecting the freedom of users to use, modify, and distribute software. It requires that any modifications or derivative works of GPL-licensed software must also be released under the GPL. On the other hand, the AGPL extends this requirement to software that is accessed over a network, such as web applications. This means that if you use AGPL-licensed software to build a web application, you must make the source code of the application available to users who interact with it over the network.

Compatibility

Another important consideration when choosing between AGPL and GPL is compatibility with other licenses. The GPL is known for its strong copyleft provisions, which require that any derivative works of GPL-licensed software must also be released under the GPL. This can sometimes create compatibility issues with other licenses, especially more permissive licenses like the Apache License or the MIT License. On the other hand, the AGPL is designed to be more compatible with other licenses, making it easier to combine AGPL-licensed code with code licensed under different terms.

Use Cases

Both AGPL and GPL are widely used in the open-source community, but they are often chosen for different use cases. The GPL is a popular choice for projects that want to ensure that their code remains open and free for anyone to use, modify, and distribute. It is commonly used for libraries, frameworks, and other software components that are intended to be widely shared and reused. On the other hand, the AGPL is often chosen for projects that involve web applications or other software that is accessed over a network. The AGPL's network copyleft provisions make it a strong choice for projects that want to ensure that the source code of their software remains accessible to users.

Enforcement

Enforcement of open-source licenses is a complex and often contentious issue. Both AGPL and GPL rely on the legal system to enforce their terms, but they have different mechanisms for doing so. The GPL relies on copyright law to enforce its copyleft provisions, allowing copyright holders to take legal action against violators. The AGPL, on the other hand, includes an additional clause that requires users who violate the license to provide access to the source code of the software on a network server. This makes it easier for copyright holders to enforce the terms of the license, as they can point to specific instances of non-compliance.

Community and Support

One of the key benefits of using open-source licenses like AGPL and GPL is the vibrant community of developers and organizations that support and contribute to the software. Both licenses have strong communities that provide resources, support, and guidance to users of the software. The GPL, with its long history and widespread adoption, has a large and active community that can provide assistance with understanding and complying with the terms of the license. The AGPL, while less widely used than the GPL, also has a dedicated community that can offer support and guidance to users of AGPL-licensed software.

Conclusion

In conclusion, both AGPL and GPL are powerful open-source licenses that promote the sharing and collaboration of software code. While they have some similarities, such as their commitment to open-source principles, they also have key differences that developers and organizations need to consider when choosing which license to use for their projects. By understanding the scope of application, compatibility, use cases, enforcement mechanisms, and community support of AGPL and GPL, developers can make informed decisions about which license best suits their needs.