Trevor Anderson

Split sidebars and widget areas into responsive columns.
Two simple widgets are provided, “Layout: New Column” and “Layout: New Column on New Row”.
Simply place these in your widget area where you’d like to create a new column (split) or new row of columns.
Gutter size and responsive collapse options are available in the Customizer -> Widget Columns panel.

Tuxedo Responsive Widget Columns

Just tested this plugin, and it works exactly as I hoped for. I can now have complex layouts in any widget areas. 
Of course it's best used for horizontal widget areas like footers, etc...



Works perfectly!

Split sidebars and widget areas into responsive columns.

Edwin Cromley

Major features in BE REST Endpoints include:
Sidebars and Widget endpoints for the WP REST API v2.
More improvements will come.
<h3>Disclaimer</h3>
This plugin has not been tested for all themes.
It is possible that this plugin may not work as intended depending on your theme or if a plugin is modifying the underlying Widgets API.
Themes that are built on top of _s (http://underscores.me) and default themes should work fine.
If you are having issues please contact us at (http://be-webdesign.com/contact/)
Also important to note is that this plugin is more of an experiment and should not be used on a production environment.
Improvements to the JSON schema and inference of schema data from widgets will need to be improved before this plugin is secure.
This plugin is mainly just an illustration of one possibility for a widgets and sidebars endpoint in the WP REST API v2.
<h3>Donations</h3>
Coming soon, maybe.

BE REST Endpoints

Major features in BE REST Endpoints include:

Tuxedo Responsive Widget Columns vs BE REST Endpoints