Voilà turns Jupyter notebooks into standalone web applications.
Unlike the usual HTML-converted notebooks, each user connecting to the Voilà tornado application gets a dedicated Jupyter kernel which can execute the callbacks to changes in Jupyter interactive widgets.
This extension allows you to render a Notebook with Voilà, so you can see how your Notebook will look with it.
You can download a test notebook with the following command:
$ wget --no-check-certificate https://jupyter-jsc.fz-juelich.de/static/files/voila_basics.ipynb
and get a preview of it with the button at the top of your notebook.