Regex Tester & Builder
Test, debug, and learn regular expressions with real-time matching, explanations, and common patterns.
Pattern Configuration
Define your regular expression pattern and options
//g
Find all matches
Case insensitive
^ and $ match line breaks
. matches newlines
Use $1, $2, etc. to reference capture groups in replacement
Test & Results
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70 characters
Hello World! This is a test string with various words and numbers 123.
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Common Regex Patterns
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Email Address
Validates email addresses with proper format
/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/
Example: user@example.com
Phone Number (US)
Matches US phone numbers in various formats
/^\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$/
Example: (555) 123-4567
URL/Website
Matches HTTP/HTTPS URLs and websites
/^https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)$/
Example: https://www.example.com/path
IPv4 Address
Validates IPv4 addresses (0.0.0.0 to 255.255.255.255)
/^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/
Example: 192.168.1.1
Strong Password
At least 8 chars with upper, lower, number, special character
/^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$/
Example: MyPass123!
Credit Card
Matches major credit card number formats
/^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|3[47][0-9]{13}|3[0-9]{13}|6(?:011|5[0-9]{2})[0-9]{12})$/
Example: 4111111111111111
Date (YYYY-MM-DD)
Validates ISO date format
/^\d{4}-\d{2}-\d{2}$/
Example: 2024-12-31
Time (24 Hour)
Validates 24-hour time format
/^([01]?[0-9]|2[0-3]):[0-5][0-9]$/
Example: 14:30 or 09:15
Social Security
Matches US Social Security Number format
/^\d{3}-\d{2}-\d{4}$/
Example: 123-45-6789
Regex Reference Guide
Basic Metacharacters
.Any character*Zero or more+One or more?Zero or one^Start of string$End of string
Character Classes
\dAny digit [0-9]\wWord character\sWhitespace[abc]a, b, or c[a-z]Lowercase range[^abc]Not a, b, or c
Quantifiers
{3}Exactly 3{3,}3 or more{3,5}Between 3-5*?Lazy zero or more+?Lazy one or more??Lazy zero or one
Groups & Assertions
(abc)Capture group(?:abc)Non-capture\bWord boundary(?=abc)Positive lookahead(?!abc)Negative lookaheada|ba OR b