Open Source Licenses - Explained

Wikipedia defines an open-source license as a type of license for computer software and other products that allows the source code, blueprint, or design to be used, modified, and/or shared under defined terms and conditions.

The open-source licenses need to be approved by OSI i.e. Open Source Initiative. OSI was formed in 1998. They describe themselves as:

The Open Source Initiative (OSI) is a non-profit corporation with global scope formed to educate about and advocate for the benefits of open source and to build bridges among different constituencies in the open-source community.

GNU General Public License (GPLv3)

Permissions of this strong copyleft license are conditioned on making available the complete source code of licensed works and modifications, which include larger works using a licensed work, under the same license. Copyright and license notices must be preserved. Contributors provide an express grant of patent rights.

• Copyleft means that any software that is written under this license needs to be released as open-source. 
• The result is that any software that uses any component which is under GPL (regardless of its percentage in the entire code) is required to release its full source code and all of the rights to modify and distribute the entire code.
• Modification of the software must be released under the same license.
• Source code must be available when the licensed material is distributed.
• Changes made to the license must be materialized. 
• The license provides an express grant of patent rights from contributors i.e. if the owner sues anyone for the patent, they lose the rights to the software.

Apache License 2.0

A permissive license whose main conditions require preservation of copyright and license notices. Contributors provide an express grant of patent rights. Licensed works, modifications and larger works may be distributed under different terms and without source code.

• Modifications to the software can be released under any license.
• The source code does not need to be made public.
• Changes made to the source code must be documented.
• The license provides an express grant of patent rights from contributors i.e. if the owner sues anyone for the patent, they lose the rights to the software.
• This license explicitly states that it does NOT grant trademark rights, even though licenses without such a statement probably do not grant any implicit trademark rights.

Mozilla Public License 2.0

Permissions of this weak copyleft license are conditioned on making available the source code of licensed files and modifications of those files under the same license (or in certain cases, one of the GNU licenses). Copyright and license notices must be preserved. Contributors provide an express grant of patent rights. However, a larger work using the licensed work may be distributed under different terms and without source code for files added to the larger work.

• The source code needs to be made public.
• Modifications of existing files must be released under the same license when distributing the licensed material. In some cases, a similar or related license may be used.
• This license explicitly states that it does NOT grant trademark rights, even though licenses without such a statement probably do not grant any implicit trademark rights.

MIT License

A short and simple permissive license with conditions only requiring preservation of copyright and license notices. Licensed works, modifications and larger works may be distributed under different terms and without source code.

• The source code doesn’t need to be public when a distribution of the software is made.
• Modifications to the software can be released under any license.
• Changes made to the source code may not be documented.
• It offers no explicit position on patent usage.

Berkeley Software Distribution (BSD v3)

A permissive license similar to the BSD 2-Clause License, but with a 3rd clause that prohibits others from using the name of the project or its contributors to promote derived products without written consent.

• The source code doesn’t need to be public when a distribution of the software is made.
• Modifications to the software can be released under any license.
• Changes made to the source code may not be documented.
• It offers no explicit position on patent usage.
• A copy of the license and copyright notice must be included with the licensed material.
• The BSD 3-clause states that the names of the author and contributors can’t be used to promote products derived from the software without permission.

Adding LICENSE to GitHub Repository

• Go to your repository online (on the website).
• Click on Add file and then Create a new file.
• Type, LICENSE as a file name, and on the right side you will see a button Choose a license template. Choose the license you want. 
• Click on Review and submit from the right side. 
• Now add the commit message on the bottom and click on commit changes or save.

We hope this helps. If any suggestions or doubts you can add a comment and we will reply as soon as possible.