Regex Tester
Test and debug regular expressions online with visual match highlighting.
Regex Flags
Test String
Results
Enter a test string to see matches
What are Regular Expressions?
Regular expressions (regex) are powerful patterns used to match, search, and manipulate text. They provide a concise way to describe complex string patterns, making them essential for text processing, validation, and data extraction.
Basic Regex Syntax
- . - Matches any single character (except newline)
- ^ - Matches the start of a string
- $ - Matches the end of a string
- * - Matches zero or more of the preceding element
- + - Matches one or more of the preceding element
- ? - Matches zero or one of the preceding element
- [ ] - Character class, matches any one character inside
Regex Flags
- g (Global) - Find all matches, not just the first one
- i (Ignore Case) - Case-insensitive matching
- m (Multiline) - ^ and $ match line breaks
- s (Dot All) - . matches newline characters
- u (Unicode) - Enable Unicode property escapes
- y (Sticky) - Matches only from the lastIndex position
Common Regex Patterns
- Email: /^[^\s@]+@[^\s@]+\.[^\s@]+$/
- URL: /^https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)$/
- Phone: /^\+?[1-9]\d{1,14}$/
- IP Address: /^(?:[0-9]{1,3}\.){3}[0-9]{1,3}$/
- Date (YYYY-MM-DD): /^\d{4}-\d{2}-\d{2}$/