RegEx Tester
Test and debug regular expressions with real-time match highlighting and interactive pattern validation
What is a RegEx Tester?
A RegEx (Regular Expression) tester is an interactive tool that helps developers test, debug, and validate regex patterns against sample text. It provides real-time match highlighting, shows captured groups, and helps you understand how your pattern matches input data before implementing it in code.
Regular expressions are powerful pattern-matching tools used for validation (emails, phones, URLs), text extraction, search and replace operations, and data parsing. Our tester supports JavaScript regex syntax with flags like global (g), case-insensitive (i), and multiline (m).
How to Use the RegEx Tester
- Enter your regular expression pattern in the regex input field
- Select flags (g for global, i for case-insensitive, m for multiline)
- Type or paste your test text in the test string field
- View real-time match highlighting showing all matches
- Check captured groups and match details in the results panel
Common RegEx Patterns
Email Validation
Pattern: ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$
Validates email addresses with standard format including username, @ symbol, domain, and TLD.
Phone Number (US)
Pattern: ^$$?([0-9]{3})$$?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$
Matches US phone numbers in formats: (555) 555-5555, 555-555-5555, 555.555.5555
URL Validation
Pattern: ^https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b
Validates HTTP and HTTPS URLs with optional www prefix and various domain structures.
Date Format (MM/DD/YYYY)
Pattern: ^(0[1-9]|1[0-2])\/(0[1-9]|[12][0-9]|3[01])\/\d{4}$
Matches dates in MM/DD/YYYY format with proper month (01-12) and day (01-31) validation.
Why Use Our RegEx Tester?
- ✓Real-time testing - see matches instantly as you type your pattern and test strings
- ✓Visual highlighting - clearly see all matches and captured groups with color-coded highlighting
- ✓JavaScript syntax - supports full JavaScript regex syntax with all standard flags and features
- ✓Free and private - test unlimited patterns, completely free, all processing done in your browser