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.

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.

Enter full screen mode and enjoy working with regular expressions. No distractions. Just you and your patterns.

It's good to see subexpressions. Just press cmd+shift+} or cmd+shift+{.

Expressions highlight not only text group but it highlights pattern group as well.

Application lets you to save your expressions, so you can always get back to them.

Whatever you write it works instantly. Type your pattern and see the results. Modify your test expression and check if it still works.

Always forgetting regular expression syntax? Just press cmd+r and check out the reference sheet.

Your pattern looks not only nice, but it's easy to read.

Forget about buttons. Just type your pattern and test expression. See the results immediately.

Testimonials

(...) 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.(...) Sojourner Hardeman

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. @reylinxu