Licenses & Standards

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About Open Source Licenses

Open source licenses are licenses that comply with the Open Source Definition — in brief, they allow software to be freely used, modified, and shared. To be approved by the Open Source Initiative (also known as the OSI), a license must go through the Open Source Initiative's license review process.

Popular Licenses

The following OSI-approved licenses are popular, widely used, or have strong communities:

All Approved Licenses

Many other licenses are also OSI-approved, but fall into other categories, such as special-purpose licenses, superseded licenses, or retired licenses. Complete lists that include all approved licenses are available:

Questions?

The OSI maintains a FAQ, which includes a lot of useful background on open source licensing, including:

For more information about open source licenses and in particular about the Open Source Initiative's approval process, see:

To promote and protect open source software and communities...

For over 20 years the Open Source Initiative (OSI) has worked to raise awareness and adoption of open source software, and build bridges between open source communities of practice. As a global non-profit, the OSI champions software freedom in society through education, collaboration, and infrastructure, stewarding the Open Source Definition (OSD), and preventing abuse of the ideals and ethos inherent to the open source movement.

Open source software is made by many people and distributed under an OSD-compliant license which grants all the rights to use, study, change, and share the software in modified and unmodified form. Software freedom is essential to enabling community development of open source software.