Expressions allows to play with regular expressions*. Just type your pattern and some text to test it. All the changes are updated while you're typing text or pattern. App highlights the syntax, so the pattern is easy-to-read and modify. If you use subexpressions (groups), you can highlight them by pressing cmd+shift+] (or [ – for decreasing the highlighted group number).
If you don't remember the regex syntax, just press cmd+r or click button in the top-right. You will get the reference sheet, so you don't have to remember everything.
The user interface is very minimalistic and non-distractive. By default the color is the same as your menubar, but you can always switch to dark or light mode (see: Preferences). You can also open app in beautiful full screen mode which is perfect when you want to focus or to demonstrate regular expressions to other people.

* Expressions uses ICU regular expression standard. More information you will find here:

What’s New

Version 1.3.1

- fixed bug that appeared on macOS 10.11

Ratings and Reviews

3.2 out of 5
5 Ratings

5 Ratings

FeatureRequesterGuy ,

Feature request

Really enjoy this app. Nice not to have to use a Web app based tool .

However i would LOVE the ability to use my system font and to increase font size for the app from preferences.


Developer Response ,

It will be implemented in future versions

Schlaeps ,

Best Looking Regex App, Not Most Full Featured

This is easily the best looking regex app. The default appearance is perfect for quick construction / testing of a matching regex, but it lacks features I would expect in an app like this like a list of all capture groups, replace support, and per-expression regex options (case insensitivity, multiline, etc. are available in the preferences, but get applied globally, rather than per expression)

rysmax ,

Did not live up to expectations

I expected that the application will show different groups.
But it shows everything monolithically.
Text for example: "...1...2...3..."
Expression for example: "(?<char1>1).*(?<char2>2)"
Application result: hightlighted symbols "1...2"
Expected result: hightlighted symbols "1", "2"
PHP preg_match result: ["0" => "...1...2...3...", "char"' => "1", "char2" => "2"]
p.s. See the RegExRX for view the "ideal" visualization of result.

Developer Response ,

By default Expressions highlights the 0th group which is the whole regex.
To highlight a group, press cmd+shift+} (Menu View -> Highlight next group).

App Privacy

The developer, Apptorium, has not provided details about its privacy practices and handling of data to Apple.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.