Regex Tester
Test and debug regular expressions with real-time matching and highlighting.
Common flags: g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode), y (sticky)
About Regex Testing
This tool helps you test and debug regular expressions in real-time. Enter a regex pattern, add flags if needed, and see matches highlighted in your test text. Perfect for developers working with text processing and validation.
About this Regex Tester
Test and debug regular expressions with real-time matching and highlighting. Our regex tester provides an interactive environment to write, test, and refine regular expressions. See matches highlighted in real-time, test against multiple strings, and understand how your patterns work. Perfect for developers learning regex, debugging complex patterns, or validating regular expressions before using them in code. Essential for anyone working with pattern matching, text processing, or data validation.
Key Features
Real-time regex matching and highlighting
Test against multiple input strings
Visual match highlighting
Support for all regex flags (global, case-insensitive, multiline, etc.)
Match groups and capture groups display
Error detection and reporting
Copy regex patterns for use in code
Works entirely in your browser for privacy
How to Use
Enter your regular expression pattern in the regex field
Add test strings in the input field
Select regex flags (global, case-insensitive, etc.)
View real-time match results
See highlighted matches in the input text
Review match groups and captured groups
Debug and refine your pattern as needed
Copy the final regex for use in your code
Popular Use Cases
Learn and practice regular expressions
Debug complex regex patterns
Test regex before using in code
Validate email, phone, or other data formats
Extract specific patterns from text
Test regex for form validation
Understand how regex patterns work
Create and refine regex for text processing
Tips & Best Practices
Start with simple patterns and build complexity
Use flags appropriately (global for multiple matches, case-insensitive for flexibility)
Test with various input strings including edge cases
Use capture groups to extract specific parts
Escape special characters when matching literals
Test with both matching and non-matching strings
Review match groups to understand pattern behavior
Frequently Asked Questions
What is a regular expression?
A regular expression (regex) is a pattern that describes a set of strings. It's used for pattern matching, searching, and text manipulation in programming and text processing.
What regex flavors are supported?
The tool typically supports JavaScript regex syntax, which is similar to other common regex flavors. Check the tool documentation for specific syntax support.
Can I test multiple strings at once?
Yes, you can test your regex against multiple input strings. The tool will show matches for each string separately.
What are regex flags?
Regex flags modify how the pattern is matched. Common flags include: g (global - find all matches), i (case-insensitive), m (multiline), and s (dotall).