Oxygen is a Java-based XML editor with support for XML, XSL, TXT, XSD, and DTD documents. The program validates XML, XSL, and XSD content, reporting eventual errors with description and line number information. Oxygen offers end tag autocompletion and a powerful code insight that guides the user to write valid XML content. Features include Unicode support and interface messages that are translated in English, French, German, Italian, and Romanian.

The editor can be used as an applet. Corporations can use it to reduce the overhead of installing and upgrading the editor on a large number of workstations. The editor has built-in support for Formatting Objects processing. It allows generation of the PDF, PS, and TXT from the result of an XSLT or directly from an FO file. It makes persistent the XML transformation settings for the edited file. Easily transform text content into an XML document by using the Enclose In option in the context menu. This is similar to the CodeInsight mechanism and is accessible on the right-click pop-up menu after selecting some text. The editor will automatically load the last project. Version 2.0.2 allows for Relax NG schema validation - documents can be validated against Relax NG schema. Also import HTML documents as XHTML - HTML documents are converted to XHTML during import.