List of FSF approved software licenses

This is a comparison of published free software licenses and open-sources e licenses. The comparison only covers software licenses with a linked article for details, approved by at least one expert group at the FSF, the OSI, the Debian project, or the Fedora project. For a list of licenses not specifically intended for software, see List of free content licenses.

FOSS stands for "Free and Open Source Software". There is no one universally agreed-upon definition of FOSS software and various groups maintain approved lists of licenses. The Open Source Initiative is one such organization keeping a list of open-source licenses. The Free Software Foundation maintains a list of what it considers free. FSF's free software and OSI's open-source licenses together are called FOSS licenses. There are licenses accepted by the OSI which are not free as per the free software definition. The open source definition allows for further restrictions like price, type of contribution and origin of the contribution, e.g. the case of the NASA Open Source Agreement, which requires the code to be "original" work. The OSI does not endorse FSF license analysis (interpretation) as per their disclaimer.

The FSF's Free Software definition focuses on the user's unrestricted rights to use a program, to study and modify it, to copy it, and redistribute it for any purpose, which are considered by the FSF the four essential freedoms. The OSI's open-source criteria focuses on the availability of the source code and the advantages of an unrestricted and community driven development model. Yet, many FOSS licenses, like the Apache license, and all Free Software licenses allow commercial use of FOSS components.

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