Open-source software is any kind of program where the developer behind it chooses to release the source code for free. Whenever software has an open-source license, it means anyone in the world can download, modify, and distribute it without paying fees to its original creator.
Since the open-source movement took off as a software development philosophy at the end of the 1990s, it’s changed the world. Estimates even suggest that a mind-blowing 96% of all web servers globally are running on some form of open-source Linux operating system, for example.
It’s important to remember that open source doesn’t just mean “free”. Lots of companies release their software for free but maintain full copyright ownership of their code, so other developers aren’t able to modify it. By contrast, successful open source initiatives are built on the hard work of potentially thousands of collaborators who have voluntarily given up their time to create something awesome.
Such an accessible development system has some serious advantages. Open-source software is often more secure because people from around the world scrutinize new releases and bugs get reported and addressed fast. Also, people are motivated to add cool new features to open source platforms which means open-source software is often just as good, if not better, than competing pay-to-use programs.
In the list below you’ll find SANS Institute’s open-source software options, sorted by type. Each piece of software is feature-rich and highly customizable.