The three basic licenses

The three basic licenses

Let’s dive into the details on the three most prevalent licenses today. The GNU general public license, or known as the GPL, the MIT license, and the Apache v2 License.

These three are the best representatives of the academic permissive category, the MIT, the copy left, the GPL, and the commercial permissive category, the Apache.


  • It is one of the most extensive open source licenses available today.

  • It’s also one of the few open source licenses that is actually treated and considered as a license, as apposed to a contract. This is because of paragraph nine, which states you are not required to accept this license in order to receive or run a copy of the program. An essential component of any contract is acceptance. If one is not required to accept the license then no contract exists. With the GPL just possessing a copy does not require acceptance.

  • Under the GPL, you can make modifications and never release them outside your organization. There is no obligation under the GPL to share those modifications, unless and until you release the software. It is worth noting that nowhere in the GPL license is the term release defined. Therefore, if you were to make code available outside your organization you couldn’t hold some of those changes back, nor could you prevent others from holding those same changes back, as that would be a violation of the GPL license.

  • There are two versions of the GPL available today, version two and three. The basic differences between the two are as follows:

    • version three contains compatibility guides on how to combine software under different open source licenses with the GPL.

    • Version three also contains specific patent license grant language.

  • If you take GPL base code and add it to non-GPL base code the resulting code base is considered a derivative work that becomes covered under the GPL.

  • The Free Software Foundation owns the copyright to the GNU licenses, which includes the GPL, the LGPL, and the AGPL.


  • Of the licenses presented in this lesson, the MIT license is the most similar to the BSD license presented earlier in this course. Like the BSD, the MIT has academic roots. In this case the Massachusetts Institute of Technology.

  • the MIT license concerns itself with stating explicitly that anybody who obtains a copy of license software is free to use, copy, modify, merge, publish, distribute, sub-license and or sell copies of the software.

  • One major difference with the MIT license as compared to the GPL, is that the MIT license is completely silent as to having to share modifications.

  • With the MIT, you are free to include MIT covered code in your proprietary code without the worry of the resulting code being subject to the MIT license. This, of course, is very different from the GPL license.

  • With the MIT license, you are free to create derived works and should you desire, license that derived work under a completely different license.


  • The final license that will be covered in this lesson is the Apache License, which is now at version 2.

  • This license is considered to be the most commercially favorable of all the open-source licenses.

  • This license is administered by the Apache Software Foundation and you can find their site at

  • like the MIT, you’re free to include Apache code in your proprietary code without the worry of affecting the copyright status of your existing proprietary code.

  • Unlike the GPL and MIT licenses, the Apache License has an embedded contributor license agreement. A contributor license agreement is an agreement between the project and a contributor. Its purpose is to ensure that there is rights clearance for the project as to any rights the contributor has to the code. These rights would primarily include any copyright or patent rights. It is very important for a project to ensure that it has rights to all the code that it receives.