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Open Source Licenses

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 (as defined in the 2006 Proliferation Report):

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Many other licenses are also OSI-approved, but fall into other categories, such as special-purpose licenses, superseded licenses, or retired licenses.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: