Developer Install

The core Jupyter Widgets packages are developed in the git repository.


To install ipywidgets from git, you will need:

Installing With Conda

conda create -c conda-forge -n ipywidgets yarn notebook
conda activate ipywidgets
ipython kernel install --name ipywidgets --display-name "ipywidgets" --sys-prefix
pip install --pre jupyterlab
git clone
cd ipywidgets

Notice that we install the prerelease of JupyterLab currently, which is only available via pip.

Rebuilding after making changes

To build and test changes, run the following commands in the ipywidgets repository root directory, empty your browser’s cache, and refresh the page.

    yarn run clean
    yarn run build

If your changes are confined to one package (for example, just in the widgetsnbextension package), then it may be sufficient to just run yarn run build in that specific directory.

Tips and troubleshooting

  • If you have any problems with the above install procedure, make sure that permissions on npm and pip related install directories are correct.

  • Sometimes, it helps to clear cached files too by running git clean -dfx from the root of the cloned repository.

  • When you make changes to the Javascript and you’re not seeing the changes, it could be your browser is caching aggressively. Try clearing the browser’s cache. Try also using “incognito” or “private” browsing tabs to avoid caching.

  • If troubleshooting an upgrade and its build, you may need to do the following process:

    • Deep clean of the cloned repository:

      git clean -dfx .
    • Remove anything with widgetsnbextension in the name of files within the conda directory

    • Try reinstalling ipywidgets

Updating widget model specification

To update the widget model specification with changes, do something like this in the repo root:

python ./packages/schema/ > packages/schema/

Releasing new versions

See for a details on how to release new versions of ipywidgets to PyPI and jupyter-widgets-controls on npm.


See for a details on how to run Python and Javascript tests.

Building documentation

See for a details on how to build the docs.