Key features of i3 are correct implementation of XrandR, horizontal and vertical columns (think of a table) in tiling. Also, special focus is on writing clean, readable and well documented code. i3 uses xcb for asynchronous communication with X11, and has several measures to be very fast. Please be aware that i3 is primarily targeted at advanced users and developers.
acquired package info from repodata DB: repodata/1878cc60a19e65efc93d1a539275c5a6799b0acbd7796ee105712c44cae47ab4-primary.sqlite.bz2
This module connects to the i3 window manager using the UNIX socket based IPC interface it provides (if enabled in the configuration file). You can then subscribe to events or send messages and receive their replies.