Open source software is similar in idea to "free software" but slightly less rigid than the free software movement. Users of open source software are (generally) able to view the source code, alter and re-distribute open source software. There is however less of an emphasis in the open source movement, the right of information and source code to be free and in some cases companies are able to develop proprietary products based on an open source.

In general, open source refers to any program whose source code is made available for use or modification as users or other developers see fit.(Historically, the makers of proprietary software have generally not made source code available).Open source software is usually developed as a public collaboration and made freely available.

An open source program has its source code distributed allowing programmers to alter and change the original software as much as they like.