RegEx Lab allows you to test regular expressions. The app highlights and underlines text to show matches and capture groups. There's also a handy cheatsheet and a results list view. It has a replace feature too.
Free • Proprietary
What is RegEx Lab?
RegEx Lab - test regular expressions
• Highlighting of regex syntax and of matches and capture groups. • Results List View which lists all the matches and capture groups. • Replace feature • Dark theme (by default) based on the Solarized colour palette • Themes to chose from (light/dark) • A handy cheatsheet which tells you about the different operators, option flags and metacharacters. • An extra row of keyboard keys for common special characters • Undo / Redo quick access buttons • Support for Dynamic Type (iOS Settings Text Size) • Works perfectly with iOS Multitasking - in Split View or as a Slide Over app. • Export / Import feature • Completely free, no ads.