Regex Tester

Why Test Regular Expressions?

Regular expressions are powerful but notoriously tricky to write correctly. A single misplaced quantifier can match too much or too little. Our regex tester gives you instant visual feedback so you can iterate quickly, see exactly what matches, and debug capture groups before shipping code.

Features

  • Real-time matching — matches update as you type the pattern or test text.
  • Configurable flags — global (g), case-insensitive (i), multiline (m), and more.
  • Capture groups — see numbered groups for each match in a clear table.
  • Match positions — start and end indices for every match.
  • Error reporting — invalid patterns are caught and displayed as friendly messages.

Common Use Cases

  • Writing email, URL, or phone number validators for form inputs.
  • Extracting data from log files, CSV rows, or HTML markup.
  • Building search-and-replace patterns for code refactoring.
  • Learning regex syntax with instant visual feedback.

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