Regex Tester

Test and debug regular expressions in real-time. See matches highlighted with group information.

Regular Expression

//g

Flags

g - Global

i - Case Insensitive

m - Multiline

Test String

How to Use Regex Tester

Enter your regular expression pattern in the input field
Toggle the flags (global, case insensitive, multiline) as needed
Enter or paste text to test against in the test string field
See matches highlighted in real-time with their positions
Review match details including capture groups and named groups

What is Regular Expression?

A regular expression (regex) is a sequence of characters that defines a search pattern. It is used for pattern matching within strings, text search and replace, input validation, and data extraction. Regular expressions are supported in most programming languages and text editors.

Common Regex Patterns

[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,} - Email address
https?://[\w.-]+(?:/[\w.-]*)? - URL (http/https)
\+?[\d\s()-]{10,} - Phone number
\b(?:\d{1,3}\.){3}\d{1,3}\b - IP address (IPv4)
\d{4}-\d{2}-\d{2} - Date (YYYY-MM-DD)
\d{2}:\d{2}(?::\d{2})? - Time (HH:MM:SS)
#[0-9A-Fa-f]{6}\b - Hex color code
<([a-z]+)[^>]*>.*?</\1> - HTML tag
\b\d{4}[- ]?\d{4}[- ]?\d{4}[- ]?\d{4}\b - Credit card number
\b\d{5}(?:-\d{4})?\b - Postal/ZIP code (US)
^[a-zA-Z0-9_]{3,16}$ - Username (alphanumeric)
^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)[a-zA-Z\d]{8,}$ - Strong password
\s+ - Whitespace

Regex Flags Explained

g (Global) - Find all matches rather than stopping after the first match
i (Case Insensitive) - Makes the pattern case-insensitive (A-Z matches a-z)
m (Multiline) - ^ and $ match the start and end of each line, not just the whole string

Example Patterns

Match digits only \d+
Match words \w+
Match email domain @([\w.-]+)
Extract quoted text ["'][^"']*["']
Match file extension \.(\w+)$

Features

Real-time pattern matching and highlighting
Support for global, case-insensitive, and multiline flags
Display of all matches with their positions
Named capture groups support
Detailed match information with index positions
Instant error feedback for invalid patterns
Works entirely in your browser - no data is sent to any server