🔍 Regex Tester

Test JavaScript regular expressions.

Regex

 
 
 
  
 
  
 
 
 
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 How it works 
 
How it works
 
Patterns are compiled with JavaScript's RegExp engine. Using String.matchAll lists all non‑overlapping matches.
 
     
  • Flags: g (global), i (case‑insensitive), m (multiline), s (dotAll), u (Unicode), y (sticky).
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  • Some features (lookbehind) require modern engines; older browsers may not support them.
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  • Beware of catastrophic backtracking in poorly designed patterns.
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 Privacy & Security 
Everything runs locally.
 
  
 
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 Accuracy, Limits & Tips 
Lookbehind support depends on your browser.
 
 
 Examples 
  • Find all email-like substrings in text.
 
 
 
 
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Looking for broader guides and best practices? Visit the ToolsAreUs Blog for indexes (like the full tool list) and articles (e.g. secure password generation).