Open-source software development (OSSD) is the process by which open-source software, or similar software whose source code is publicly available, is developed by an open-source software project. These are software products available with its source code under an open-source license to study, change, and improve its design. Examples of some popular open-source software products are Mozilla Firefox, Google Chromium, Android, LibreOffice and the VLC media player.
In 1997, Eric S. Raymond wrote The Cathedral and the Bazaar. In this book, Raymond makes the distinction between two kinds of software development. The first is the conventional closed-source development. This kind of development method is, according to Raymond, like the building of a cathedral; central planning, tight organization and one process from start to finish. The second is the progressive open-source development, which is more like "a great babbling bazaar of differing agendas and approaches out of which a coherent and stable system could seemingly emerge only by a succession of miracles." The latter analogy points to the discussion involved in an open-source development process.
Differences between the two styles of development, according to Bar and Fogel, are in general the handling (and creation) of bug reports and feature requests, and the constraints under which the programmers are working. In closed-source software development, the programmers are often spending a lot of time dealing with and creating bug reports, as well as handling feature requests. This time is spent on creating and prioritizing further development plans. This leads to part of the development team spending a lot of time on these issues, and not on the actual development. Also, in closed-source projects, the development teams must often work under management-related constraints (such as deadlines, budgets, etc.) that interfere with technical issues of the software. In open-source software development, these issues are solved by integrating the users of the software in the development process, or even letting these users build the system themselves.