Regex Visualizer & Debugger

Test and debug your regular expressions with real-time highlighting and human-readable explanations. Build and validate regex patterns with confidence.

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Test Your Regex Pattern

Enter your regular expression and test string to see matches highlighted in real-time. Get instant explanations of what your pattern does.

g
The quick brown fox jumps over the lazy dog. 1234567890
Explanation
Enter a pattern to see the explanation.
Match Information
Found 0 matches.

Common Regex Patterns

Email Validation

^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$Validates email addresses with common formats

URL Matching

https?://[^\s]+Matches HTTP and HTTPS URLs

Phone Numbers

^\+?1?\d{9,15}$Matches international phone numbers

Date (YYYY-MM-DD)

^\d{4}-\d{2}-\d{2}$Matches ISO 8601 date format

IP Address

^(\d{1,3}\.)3\d{1,3}$Matches IPv4 addresses

Hex Color

^#?([a-fA-F0-9]{6}|[a-fA-F0-9]{3})$Matches hex color codes

Regex Fundamentals

Essential concepts for mastering regular expressions

Character Classes

Define sets of characters to match. Use [abc] to match a, b, or c, or [a-z] for ranges.Examples: [0-9] (digits), [A-Za-z] (letters), \d (digit), \w (word character)

Quantifiers

Specify how many times a pattern should match. Use *, +, ?, or {n,m} for precise control.Examples: * (0 or more), + (1 or more), ? (0 or 1), {3} (exactly 3)

Capture Groups

Extract parts of matched text using parentheses. Use (pattern) to create groups for extraction or backreferences.Examples: (abc), (?:abc) (non-capturing), \1 (backreference)

Frequently Asked Questions

Common questions about regular expressions

What is a regular expression (regex)?

A regular expression (regex) is a sequence of characters that defines a search pattern. It's used for pattern matching, text validation, search and replace operations, and data extraction.

How do I test a regex pattern?

Use our regex tester to enter your pattern and test string. The tool will highlight matches in real-time and provide explanations of what each part of your regex does.

What are common regex metacharacters?

Common metacharacters include: . (any character), * (zero or more), + (one or more), ? (optional), ^ (start), $ (end), [ ] (character class), and ( ) (capture group).

What is the difference between greedy and lazy matching?

Greedy matching (default) matches as much as possible, while lazy matching (using ?) matches as little as possible. For example, .* is greedy, while .*? is lazy.