Free Regex Generator & Tester
Generate and test regular expressions with real-time matching. Create patterns for validation, extract data, and learn regex syntax.
Test String
Regular Expression Pattern
Flags
Match Results
Enter a regex pattern to see results
What is Regex Generator & Tester?
Regular expressions (regex) are powerful pattern-matching tools used in programming and text processing. They allow you to search, validate, and manipulate text based on complex patterns. Our regex generator helps you create, test, and debug regular expressions with real-time feedback, making it easier to build accurate patterns for data validation, text extraction, and string manipulation.
Key Features
- Generate regex patterns with pre-built templates
- Real-time pattern testing with instant results
- Support for all standard regex flags (global, case-insensitive, multiline, etc.)
- Visual highlighting of matches in your test text
- Capture group detection and display
- Error detection and validation
- Pre-built sample patterns for email, phone, URL, date validation
- Comprehensive regex cheat sheet reference
- Pattern builder with common regex constructs
Usage Examples
Generate Email Pattern
Generate regex pattern to validate email addresses
^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$Generate Phone Pattern
Generate regex pattern to extract phone numbers
(\+?1[-.s]?)?\(?([0-9]{3})\)?[-.s]?([0-9]{3})[-.s]?([0-9]{4})URL Detection
Find and validate URLs in text content
https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)Frequently Asked Questions
How do I generate regex patterns for common use cases?
Use our pre-built sample patterns for email validation, phone numbers, URLs, dates, and more. Click on any sample pattern to use it as a starting point, then modify it to fit your specific needs. You can also use our pattern builder to create custom regex expressions.
What are regex flags and when should I use them?
Regex flags modify how the pattern matching works. Common flags include 'g' (global - find all matches), 'i' (case-insensitive), 'm' (multiline - ^ and $ match line breaks), and 's' (dotall - . matches newlines). Use global flag when you want to find all occurrences, not just the first one.
How do I escape special characters in regex?
Use a backslash (\) before special characters to treat them literally. For example, to match a literal dot, use \. instead of . which matches any character. Common characters that need escaping: . * + ? ^ $ | \ ( ) [ ] { }
What are capture groups and how do I use them?
Capture groups are parts of your regex pattern enclosed in parentheses (). They capture and remember the matched content for later use. You can reference captured groups with $1, $2, etc., or access them in your code. Use (?:...) for non-capturing groups when you need grouping but don't want to capture.
How can I make my regex more efficient?
Use specific character classes instead of . when possible, avoid nested quantifiers, use anchors (^ and $) to prevent unnecessary backtracking, and consider the order of alternatives in your pattern. Test with realistic data to identify performance bottlenecks.