The Regex Builder application was designed to be a tool that will help you create and debug Regular Expressions.

It supports an XML file format including the source text, expression, and options to support easy debugging for non-matches from other applications.

The tool also supports partial expression execution to help you find the part of the expression which isn't matching. Finally, it shows a tree of the Matches, Groups, and Captures to quickly show you what the parts of your expression are matching.