App: RegExp
Developer: Loshadki, LLC
Genres: Developer Tools, Utilities

The only one Regular Expression tester you need, that will help you to test your regular expressions in flavors:

- Go
- Go (POSIX)
- Swift
- Objective-C
- Ecmascript (Javascript)

Most of the features are free, so you can try it! But we do request a purchase of $2.99 (US price, or equivalent in your country or currency) for ability to configure advanced regular expression options.

If you are working a LOT with regular expressions and want to keep you own database (or notebook) of regular expression, this application is for you.

The new Swift regular expression flavor is highly configurable, and you can make it compatible with some of the regular expression flavor that you use (like Python or Rust). 
JavaScript and Go regular expressions are very limited, so you want to keep them as separate flavors to use only features they provide.

If you account uses iCloud, all the regular expressions you save are going to be synced and backed up using iCloud (private to you).

Release notes:
Add a substitute flag so that the empty string text can be used as a substitution text.