Pandion is an XMPP

Extensible Messaging and Presence Protocol

Extensible Messaging and Presence Protocol is an open-standard communications protocol for message-oriented middleware based on XML . The protocol was originally named Jabber, and was developed by the Jabber open-source community in 1999 for near-real-time, extensible instant messaging , presence...

 client, developed by Dries Staelens and Sebastiaan Deckers.

Pandion is developed as a Rich Desktop Application

Rich Desktop Applications/Rich Internet Desktop Applications (RDA/RIDA)

Rich Desktop Applications/Rich Internet Desktop Applications are the next generation of client web applications. It follows the evolution from thick desktop clients towards the thin client architectures...

. This means it uses HTML

HTML

HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

, CSS

CSS

-Computing:*Cascading Style Sheets, a language used to describe the style of document presentations in web development*Central Structure Store in the PHIGS 3D API*Closed source software, software that is not distributed with source code...

 and JavaScript

JavaScript

JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....

 to make up its interface and C++

C++

C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...

for a backend. The backend embeds a web browser to host the interface and provides access to features of the operating system from the JavaScript code. Pandion is free and open source software published under the GNU General Public License version 3 or later.

RhymBox dispute

In 2004, there was some dispute over ownership of the Pandion (then RhymBox) code. The dispute was resolved in 2009 through mediation by the XMPP Standards Foundation, as described at http://xmpp.org/xsf/press/2009-11-03.shtml and http://mail.jabber.org/pipermail/jdev/2009-November/058573.html