Regular Expression Tester

Overview

Test and debug regular expressions with instant visual feedback. Highlights matches in real-time, displays capture group details, and supports multiple flags (global, case-insensitive, multiline, dotall). Whether you’re validating email addresses, extracting data from text, or debugging complex patterns, see results update live as you type.

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Tips

  • Start with simple patterns and build up complexity gradually
  • Use the global flag (g) to find all matches, not just the first one
  • Capture groups () extract parts of a match - use non-capturing groups (?:) when you don’t need extraction
  • Test with edge cases to ensure your pattern handles unexpected input
  • Common patterns: Email (\w+)@(\w+)\.(\w+), URL https?://[\w\-\.]+\.\w{2,}, Phone \d{3}-\d{3}-\d{4}, Date \d{4}-\d{2}-\d{2}
  • Use the built-in quick reference for syntax help