Kupu is an open-source client-side editor designed for use with Mozilla, Netscape, and Internet Explorer browsers. It was developed as a "document-centric" tool inspired by the Epoz editor created by Maik Jablonski.
The software was authored by Paul Everitt, Guido Wesdorp, and Philipp von Weitershausen. The project aimed to improve upon existing architecture by enhancing JavaScript code, pluggability, standards support, and configurability. Additionally, Kupu was designed to provide support for various web servers beyond Zope.