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Aivar Annamaa edited this page Mar 11, 2021 · 33 revisions


NB! The plug-in system was changed in version 3.0

Thonny can be extended with 3rd party plug-ins. Usually they are distributed via and can be installed with Tools => Mangage plug-ins.

About writing plug-ins

A 3rd-party Thonny plug-in is a Python module (or package) located under thonnycontrib (or thonnycontrib.backend) namespace package and containing the parameterless function load_plugin.

Here's an example of a plug-in which adds a command into the "Tools" menu:

from thonny import get_workbench
from tkinter.messagebox import showinfo

def hello():
    showinfo("Hello!", "Thonny rules!")

def load_plugin():

During startup Thonny locates all such modules and calls their load_plugin function.

Setting up the development

Where does the aforementioned thonnycontrib package live? As it is a namespace package, it can be spread out to several places on the Python path. This means you can either use a directory which is already on the Python path or you can create your project anywhere and run Thonny with the project directory added to the path (eg. via PYTHONPATH environment variable).

If you don't want to mess with the path then it's easiest to develop and test the plug-in under your Python's user site directory (the exact path is given in the Tools => Manage Plug-ins dialog)

An example setup (with Linux commands)

First make sure that you have installed all the required Python packages (either with pip into a virtual environment or via system tools).

The following commands show how to set up both Thonny and your plugin project with the hello plugin shown above. When you run thonny on the last line, you should see the new item in the Tools menu.


cd ~
mkdir thonny_stuff
cd thonny_stuff
git clone
mkdir -p my_plugin/thonnycontrib
cp my_plugin/thonnycontrib
export PYTHONPATH=~/thonny_stuff/my_plugin
cd thonny
python3 -m thonny

What can a plug-in do?

In short: whatever.

More pragmatically: load_plugin usually retrieves the singleton instance of the class thonny.workbench.Workbench (using thonny.get_workbench()) and calls its public methods like add_command or add_syntax_theme with suitable arguments.

At the moment these methods are not documented, so you need to read the code in thonny.workbench and/or some existing plug-ins (either 3rd party plug-ins listed above or built-in plug-ins under the thonny.plugins package)

Back-end plug-ins

Regular plug-ins work in Thonny's front-end process, but it's also possible to add plug-ins for the CPython back-end. These plug-ins must live under thonnycontrib.backend.

TODO: See ____ for an example.

How to package and distribute your plug-in?

In short: the same way as you would package and distribute any Python module or package. Just make sure your distribution name starts with thonny- and you have specified supported Thonny version range under dependencies.

Note that Thonny uses PyPI-s Json API to get information about your plug-ins dependencies (for an example search dist_requires from PyPI can extract this information only from whl files and these must be uploaded before other files (eg. tar.gz and zip).

Here is an example:

Some 3rd party plug-ins