Debian

Debian () is a free, general-purpose operating system developed by the Debian Project, a worldwide volunteer association founded by Ian Murdock on August 16, 1993. It is the second-oldest Linux distribution still being developed (only Slackware is older) and forms the base of many others.

It is deployed across servers, personal computers, and embedded devices. Among Linux distributions, it ranks second only to Ubuntu (a Debian derivative), with 16% of the overall market. According to the 2025 Stack Overflow Developer Survey, 11.4% of developers use it as their primary personal operating system and 10.4% professionally. Its emphasis on stability and long-term support over frequent package updates has made it prevalent in server and embedded deployments.

Development is led by the Project Leader and guided by two foundational documents: the Debian Social Contract, a summary of the project's commitments that includes the Debian Free Software Guidelines (DFSG), and the Debian Constitution, which describes the organizational structure. The project publishes three concurrent development branches: stable, testing, and unstable, which correspond to different levels of software maturity. The current stable release, released on August 9, 2025 and codenamed "Trixie", includes tens of thousands of packages maintained by more than a thousand active contributors.

Since 1997, the project has operated independently through Software in the Public Interest, a non-profit corporation founded by project members to hold its assets and trademarks. It previously received support from the Free Software Foundation between 1994 and 1995, with the sponsorship ending due to disagreements.