As it is with every other aspect of your business, using a third-party to supply anything is a risk. Open source software is no different, you need to know what you are getting into before you start using it. Be aware of licenses that require you to open source anything you produce that is based on the open source code you use, these are known as copyleft provisions and are a features of the GPL and LPGL licenses.
There is a lot of open source software available freely for download that solves problems you need solving. Using existing code can save you money by eliminating days of development, reducing test cycles and bringing creative solutions into your development shop. There are good reasons to use open source and it has to be a consideration in any project you undertake.
But it seems that for every snippet of open source code you find, there is a unique open source license that governs how you use, modify and distribute the open source. The Open Source Initiative, an organization that promotes open source software and approves licenses as Open Source Definition compliant, recognizes roughly seventy different open source licenses.
Fortunately, the open source world is dominated by just a few of these licenses and due to the restrictions imposed by the OSD definition, the variation between the licenses isn’t as great as you might think. The key to staying safe is to understand how the open source code you want to use is licensed before you incorporate it into your product. Its far easier to just not use a piece of code than to rip it out later.
- By far the biggest issue you need to watch for is a “Copyleft” provision. If you use open source that is subject to a copyleft license, all modifications of that open source, and any other code that is integrated with the open source must be licensed under the same terms as the original open source code. In other words, by using the open source code, you may be giving up rights to profit from the code you develop yourself.
- Copyleft has two main variations, strong and weak copyleft. Strong copyleft, which is found in one of the most popular open source licenses, the GNU Public License (GPL), forces you to open source all works derived from or using the open source code. Weak copyleft, used, for example, in the Lesser GNU Public License, allows a application that to links to an open source software library to stay outside the open source requirements, but requires any changes to the open source library to become open source.