Phosh (portmanteau of phone and shell) is a graphical user interface designed for mobile and touch-based devices initially developed by Purism.

The project is maintained and developed by a diverse community, and is the default shell used on several mobile Linux operating systems including PureOS, Mobian and Fedora Phosh.

[2] In August 2017, Purism, personal computing hardware vendors and developers of PureOS announced their intention to release a privacy-centric smartphone that ran a mobile-optimized version of their Linux-based operating system.

In April 2018, Purism started to publicly release documentation that referenced Phosh with updated mockups,[4] and hired GNOME UI/UX developer Tobias Bernard to directly contribute to the shell.

To ease testing on their devices Purism maintains a separate repository[8] that integrates some of the open upstream merge requests and provides packaging for PureOS.

[citation needed] A key part of this initiative is libadwaita, a GTK-based library that provides consistent, adaptive UI components and widgets for GNOME applications, which ensures a cohesive design language across platforms.