Regex Tester

Test regular expressions with real-time matching and highlighting. Supports JavaScript regex syntax.

Regular Expression
/ /
Test String
Match Result
Match Details

Enter a regex pattern and test string to see matches

Common Patterns
Quick Reference
Characters
  • . Any character
  • \d Digit [0-9]
  • \w Word [a-zA-Z0-9_]
  • \s Whitespace
Quantifiers
  • * 0 or more
  • + 1 or more
  • ? 0 or 1
  • {n,m} n to m times
Anchors
  • ^ Start of string
  • $ End of string
  • \b Word boundary
Groups
  • (abc) Capture group
  • (?:abc) Non-capture
  • a|b Or
  • [abc] Character class
What is Regular Expression?

Regular expressions (regex) are patterns used to match character combinations in strings. They are a powerful tool for text processing, validation, and search-and-replace operations.

Common Use Cases:
  • Email validation
  • Phone number formatting
  • Password strength checking
  • URL parsing
  • Log file analysis
  • Data extraction
Frequently Asked Questions

  • g (global) - Find all matches, not just the first
  • i (insensitive) - Case-insensitive matching
  • m (multiline) - ^ and $ match line starts/ends
  • s (dotall) - Dot (.) matches newlines too

Common issues: forgetting to escape special characters (use \. for literal dot), case sensitivity (add i flag), or anchors ^$ preventing partial matches. Try simplifying your pattern first.

This tool uses JavaScript regex syntax. Most patterns work across languages (Python, Java, etc.), but some features differ. Lookbehinds, named groups, and certain flags may vary between implementations.