An improved Python library to control i3wm.
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acrisci Raise AttributeError instead of KeyError for _ReplyType class
When getting an attribute that is not there, some people might expect to
catch AttributeError and raise any other which leads to bugs.

fixes #89
Latest commit 341eb0d Jul 17, 2018



An improved Python library to control i3wm.


i3's interprocess communication (or ipc) is the interface i3wm uses to receive commands from client applications such as i3-msg. It also features a publish/subscribe mechanism for notifying interested parties of window manager events.

i3ipc-python is a Python library for controlling the window manager. This project is intended to be useful for general scripting, and for applications that interact with the window manager like status line generators, notification daemons, and pagers.

If you have an idea for a script to extend i3wm, you can add your script to the examples folder or make a script request on the issue tracker.


i3ipc is on PyPI.

pip install i3ipc


#!/usr/bin/env python3

import i3ipc

# Create the Connection object that can be used to send commands and subscribe
# to events.
i3 = i3ipc.Connection()

# Print the name of the focused window
focused = i3.get_tree().find_focused()
print('Focused window %s is on workspace %s' %
      (, focused.workspace().name))

# Query the ipc for outputs. The result is a list that represents the parsed
# reply of a command like `i3-msg -t get_outputs`.
outputs = i3.get_outputs()

print('Active outputs:')

for output in filter(lambda o:, outputs):

# Send a command to be executed synchronously.
i3.command('focus left')

# Take all fullscreen windows out of fullscreen
for container in i3.get_tree().find_fullscreen():

# Print the names of all the containers in the tree
root = i3.get_tree()
for con in root:

# Define a callback to be called when you switch workspaces.
def on_workspace_focus(self, e):
    # The first parameter is the connection to the ipc and the second is an object
    # with the data of the event sent from i3.
    if e.current:
        print('Windows on this workspace:')
        for w in e.current.leaves():

# Dynamically name your workspaces after the current window class
def on_window_focus(i3, e):
    focused = i3.get_tree().find_focused()
    ws_name = "%s:%s" % (focused.workspace().num, focused.window_class)
    i3.command('rename workspace to "%s"' % ws_name)

# Subscribe to events
i3.on('workspace::focus', on_workspace_focus)
i3.on("window::focus", on_window_focus)

# Start the main loop and wait for events to come in.


Please feel free to report bugs, request features or add examples by submitting a pull request.


This work is available under a BSD license (see LICENSE)

Copyright © 2015, Tony Crisci

All rights reserved.