What is open source software?

Open source software does not necessarily mean that executable software is given away for free. It does, however, mean that its source code is available for free.

For instance, the source code for Red Hat® Enterprise Linux® is freely available to anyone (see for yourself), but converting that source code into runnable code requires expertise, time, and servers. When organizations want the production-ready code for Red Hat Enterprise Linux without having to reconstruct it themselves from source code, they obtain a subscription.

Open source software is also sometimes conflated with the free software movement, which can add to the confusion around whether open source means “free.” The free software movement grew out of the hacker culture of the 1970s and was formally founded by Richard Stallman as part of the GNU Project and the non-profit Free Software Foundation. Usually, “free software” is meant to emphasize a freedom in the rights of end-users, but can sometimes be confused as meaning “free of cost.”

In actuality, neither free software nor open source software denote anything about cost—both kinds of software can be legally sold or given away.

Free software and open source software share common values, and the terms are sometimes combined in the popular phrase “free and open source software” (FOSS).