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Regex Tester

Test regular expressions with real-time highlighting.

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Welcome to KoolToolz! Create Regular Expressions with ease.
MatchIndexGroups
Welcome0-
KoolToolz11-
Create22-
Regular29-
Expressions37-

About Regex Tester

The KoolToolz Regex Tester is an online debugging tool for Regular Expressions. It offers real-time highlighting to show you exactly what your pattern matches in a given text. Whether you are validating emails, extracting data, or cleaning text, this tool helps you write correct RegExp patterns faster.

Quick Reference Cheat Sheet

Character Classes

  • . Any character
  • \w Word character [a-zA-Z0-9_]
  • \d Digit [0-9]
  • \s Whitespace

Quantifiers

  • * 0 or more
  • + 1 or more
  • ? 0 or 1
  • {n} Exactly n times

Anchors

  • ^ Start of string
  • $ End of string
  • \b Word boundary

Groups

  • (...) Capturing group
  • (?:...) Non-capturing group
  • [abc] Set of characters