Regex Tester
Test regular expressions in real-time with JavaScript regex flavor.
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Quick Reference
Character Classes
. 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
Flags
g Globali Case insensitivem Multiline
About Regular Expressions
Regular expressions (regex) are patterns used to match character combinations in strings. They're incredibly powerful for text processing, validation, and search-and-replace operations.
Common Use Cases
- Email validation
- Phone number formatting
- URL parsing
- Log file analysis
- Data extraction
Tips
- Start simple and build up complexity
- Use non-greedy quantifiers (*?, +?) when needed
- Test with edge cases
- Consider using named groups for readability