Rad Software Regular Expression Designer is a free download that helps programmers learn, develop and test Regular Expressions. It is an interactive Windows application that is designed to be simple and easy to use.


  • The Regex match results are listed in a tree with levels for Matches, Groups and Captures. Clicking on a Match, Group or Capture will highlight it in the Input text window
  • Regex.Replace is supported and the results of the replace are listed in a separate window.
  • The Language Element window is an embedded reference that gets you up to speed quickly. Click on an item to see a description in the pane below, double-click a language element to add it to your Regex
  • Find text in any of the text windows with Ctrl+F
  • Flexible interface with dockable windows
  • Now supports very large values for the input text

Regular Expression Designer Main Window

.NET Framework Required

The Regular Expression Designer is requires the .NET Framework to be installed before it will run. The .NET Framework is pre-installed on Windows or can be downloaded from Microsoft.


Download Rad Software Regular Expression Designer v1.5 (~222 KB)


If you have found the Regular Expression Designer useful and you would like to make a donation please use this PayPal button.

The Regex Designer is free and there is no obligation to donate :-)

Updated to Version 1.5

The changes include: now requires .NET Framework 4

Updated to Version 1.4

The Regular Expression Designer has been updated to v1.4. The changes include:

  • Regex is run in another thread so long running expressions can be cancelled.
  • Regular Expressions can be saved to a file and reloaded.
  • A new installer program has been used. Will install on Windows vista (does not check .NET Framework version)

Getting started with the Regular Expression Designer

  1. Start the Regular Expression Designer from the Desktop shortcut or from the Start Menu
  2. Arrange the windows by dragging a window by its title to the edge of the screen or on top of another window title
  3. Enter some text to test the Regex against in the Input Text window
  4. Enter a Regular Expression in the Regular Expression window
  5. Click on the Match Expression button or press F5 to run the Regular Expression against the Input Text
  6. Matches are listed in the Match Results window
  7. Click on a Match to highlight the match within the Input Text

Learn Regular Expression Syntax

If you are not familiar with Regular Expressions see the article on this site:
Learn Regular Expression (Regex) Syntax for .NET