Butterfly XML Editor is an IDE built on top of a new real-time incremental XML parsing algorithm. The editor features syntax and error highlighting, incremental validation, code completion, XSLT pipelines, and side by side DOM and source viewing.

SOX is an alternative syntax for XML. It is useful for reading and creating XML content in a text editor. It is then easily transformed into proper XML.

Beating typographic correctness out of (X)HTML: more than you ever wanted to know about dashes, spaces, curly quotes, and other vagaries of online typography.