Reginald RegEx explorer

With a desperate need to debug a lengthy regular expression destined for use with the excellent RegexKitLite library, I have quickly put together a Mac OS X application.

Reginald icon Reginald is a kindly old gentleman devoted to assisting you with those tricky regular expressions.

Provide some sample input, and your regular expression, and Reginald will provide you with colour-coded output and a list of all your matches and the corresponding capture groups for your exploration. Select a match or capture group in the list to the right, and the corresponding text will be selected in the panel to the left.

Reginald is built on RegexKitLite, and so uses the ICU syntax.

It will run on Mac OS X 10.6 and above.

Download Reginald here, or access the source on GitHub.

Reginald screenshot

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  1. Posted September 30, 2010 at 10:07 am | Permalink

    Hi Michael,

    just wanted to say a big thanks for this. I’ve been looking for a regex debugger off and on for the Mac for several years. I came across Reginald today, it works a treat and it will be taking up a permanent place in my application folder.

    Kind regards,


  2. Posted December 29, 2011 at 2:57 pm | Permalink

    Hi Michael,

    This tool is invaluable – I use it for debugging my regexes all the time, and it’s even proven helpful as a learning aid (I’ve been using it to learn about read ahead and read behind).

    Great stuff.

    Is there any source code available? I would love to port this over to Windows…

    • Posted December 29, 2011 at 2:58 pm | Permalink

      Idiot – I just saw the source code. I’ll take a look.

    • Posted December 29, 2011 at 2:58 pm | Permalink

      Cheers, Joe, I’m glad it’s helped you!

      Source: RTFM ;-) (see above)

      • Posted December 29, 2011 at 3:01 pm | Permalink


        RTFM indeed! First time I’ve seen that acronym used by someone else, great.

  3. Jon
    Posted September 17, 2012 at 4:17 am | Permalink

    This is a great little tool, and is better than many of the regex evaluators out there. I’m an ObjC n00b. Is there anywhere to easily apply the full regex kit framework? I would love to see a more robust PCRE version of this!