xmonad is a tiling window manager for the X Window System, written in the functional programming language Haskell.
Begun in March 2007, it is similar to dwm, larswm, StumpWM and other members of the tiling window manager family, in that it arranges windows in a nonoverlapping tiled pattern and strives to make it possible for the user to productively manage windows without the use of the mouse. Xmonad is packaged and distributed on a wide range of Unix-like operating systems, such as Arch Linux, Debian, Ubuntu, Gentoo, Source Mage, NixOS, FreeBSD, NetBSD, OpenBSD, and Mac OS X.