In order to instantiate an editor, the editor designer needs to declare a document type and provide a number of stylesheets that specify the behavior of the editor. The stylesheets are then compiled to a server application. More information about instantiating an editor can be found on the Building an instance pages.
The underlying Proxima architecture was developed by Martijn Schrage at Utrecht University, as part of his PhD project (thesis available at Publications). The web-based functionality was made possible by a grand from NLnet foundation.
Proxima 2.0 is an open-source project, maintained by Martijn Schrage of Oblomov Systems. We are looking for people that can help with the development. Check out Contribute to find out how you can get involved with the project.
Below are some screenshots of editors created with Proxima 2.0. Click on the screenshot to see a larger version. A description of these editors together with the actual editors that can be tested is found in the Gallery.