Where to Download i3 and Find Its Documentation

i3wm.org is the official home of i3, a tiling window manager for GNU/Linux and BSD. From that site you can download the latest version (the page currently lists 4.25.1), read the User's Guide, and watch a screencast. The project is Free and Open Source Software under the BSD license, and it is primarily aimed at advanced users and developers.

What you can get from i3wm.org

The site presents three main entry points, each matching a different stage of getting started:

The page's own framing is "Do What I Mean. Good Docs. Clean Code. Sounds good?" — which reflects the project's stated priorities rather than a marketing claim.

Before you install: what i3 actually is

i3 is a tiling window manager written completely from scratch. Its target platforms are GNU/Linux and BSD operating systems. If you are coming from a stacking window manager, the behavior will be different: windows are arranged by a tree structure rather than overlapping freely.

Two design points are worth knowing before you commit:

• Tree structure for layouts. i3 arranges windows in a tree, which allows more flexible layouts than the column-based approach used by other window managers.
• Modes, like in vim. You can use different keybindings in a 'resize' mode than in the default mode, for example.

Documentation and code as first-class resources

The project states that it wants well readable, well documented code, and that it documents how to extend i3 by explaining its internal workings. That documentation is intended to be usable by people who know how to program but are not necessarily familiar with all of X11's internals — it explains why things happen and when they happen, so a reader can build a picture of the whole process a window manager is responsible for.

If your goal is only to use i3, the User's Guide is the relevant document. If your goal is to modify i3, the source-level documentation is the one the project points to.

Multi-monitor and rotated screens

If you use more than one display, this is a documented area of focus rather than an afterthought. i3 implements multi-monitor support by assigning each workspace to a virtual screen. The project specifically calls out making sure that attaching and detaching new monitors — such as video projectors — works during operation and does the right thing. Support for rotated monitors is also provided.

How i3 relates to wmii

i3 was informed by the experience of wanting to hack on and fix wmii. The stated goals that came out of that experience include using xcb instead of Xlib (a cleaner API, and faster in many situations) and implementing an IPC interface for other programs, with subscription to certain events and acceptance of commands. The project describes this IPC approach as more lightweight than wmii's use of the 9P filesystem, and notes that core functionality does not depend on a separate program, so i3 runs faster, especially when the system is under load.

A note on project direction

The page states that the maintainers are generally happy with the feature set of i3 and instead focus on fixing bugs and maintaining it for stability. New features will therefore only be considered if the benefit — the sentence is cut off at that point on the page — so if you are choosing i3 expecting rapid feature expansion, that is not the stated direction.

Practical next step

Go to i3wm.org, download the latest version listed there, and read the User's Guide before your first session. If you want to see the interaction model first, watch the screencast. The download page is the authoritative source for the current version number, so check it rather than relying on a version quoted elsewhere.