Regular Expressions App
Made Nice.
An app to play with regular expressions (regex) on macOS. Live preview, library, regex manual enclosed in beautiful user interface.
Expressions requires macOS 10.11 or newer


  • Minimalistic UI
    Minimalistic UI
    Forget about buttons. Just type your pattern and test expression. See the results immediately.
  • Syntax highlighting
    Syntax highlighting
    Your pattern looks not only nice, but it's easy to read.
  • Reference sheet
    Reference sheet
    Always forgetting regular expression syntax? Just press cmd+r and check out the reference sheet.
  • Live preview
    Live preview
    Whatever you write it works instantly. Type your pattern and see the results. Modify your test expression and check if it still works.
  • Expression Library
    Expression Library
    Application lets you to save your expressions, so you can always get back to them.
  • Group highlighting
    Group highlighting
    Expressions highlight not only text group but it highlights pattern group as well.
  • Easy switching between groups
    Easy switching between groups
    It's good to see subexpressions. Just press cmd+shift+} or cmd+shift+{.
  • Beautiful full screen view
    Beautiful full screen view
    Enter full screen mode and enjoy working with regular expressions. No distractions. Just you and your patterns.
  • Multiline patterns and comments
    Multiline patterns and comments
    Sometimes the pattern is too complex. Just check "Allow whitespaces and comments" option and split your pattern into smaller parts. Add some comments if you like.
  • Dark and light mode
    Dark and light mode
    It's great to have dark interface. But sometimes you just want to have a fresh look. Change your interface to Light. It still looks amazing.

What People Say?

Expressions is an easy to use, functional and also very nice looking regex tester. No more fiddly web versions ;-)
Marco Fraatz
Marco Fraatz
PhD, Academic
(...) It's a sumptuous, minimalistic, don't-make-me-think app I use to evaluate regular expressions (regex).(...) Expressions the most Mac-like of any of the regex apps I've used. In fact, after I close Expressions and go back to my Mac's desktop, my desktop feels a little shabby.(...)
Expressions is a definitely great tool for regex. It’s so simple, elegant and gorgeous that I don’t want to use any other else.

Frequently Asked Questions

  • Why does my old license not work?
    As of Expressions 1.3.5, we've changed the license system, and you need a new license number which you can get for free. Read more.
  • What regex standard does the app use?
    Expressions uses ICU. It's the standard used in Apple frameworks, so if you develop iOS/macOS apps, it's the one.
  • One time payment or subscription?
    One time payment
  • Minimum system requirements?
    macOS 10.11 or newer
  • Is Apple Silicon supported?
    Yes, since Expressions 1.3.5
  • Do you offer student discount?
    Sure! It's available through this website.