Comparing Open Source Licenses

The OpenLogic Certified Library includes hundreds of projects and over 225 different licenses. While many of these licenses are custom, most are based — at least loosely — on one of the 18 most commonly used license types. We’ve laid out for you in table form a detailed comparison of the common features of these licenses.

The three tables below compare the licenses on these general, and commonly considered, points, in increasing detail:

• Author
• Date published
• OSI Approved
• GPL Compatible
• Copyleft

For those of you new to licensing, some definitions:

GPL Compatible licenses allow the combination of the code covered by them with programs that use the GPL without conflict. Some free/open source software licenses are not GPL-compatible which means they impose conditions not in keeping with the GPL.

Copyleft licenses – of which the GPL is the most commonly used – require any work originating in the licensed code to be made available under terms identical to that specified by the license that applies to the originating code.

Comparing Licenses One to Another

Here’s a pdf of the highest level comparison…

A little more detail…

And the most detail yet…

If you’d like, you can download the entire license matrix in either Microsoft Excel (XLS) or OpenDocument Spreadsheet (ODS) format.

(From olex.openlogic.com)