Regex Tester
Test and validate regular expressions with real-time matching, syntax highlighting, and detailed explanations. Perfect for pattern matching and data validation.
Quick Examples:
How to Use Regex Tester
- Enter Pattern: Type your regular expression in the pattern field
- Set Flags: Choose global, case-insensitive, or multiline options
- Add Test Text: Enter the text you want to test against
- Test: Click "Test Regex" to see matches and results
- Refine: Adjust your pattern based on the results
Common Regex Patterns
Email Validation:
^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$
Phone Number (US):
^\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$
URL Validation:
^https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)$
Date (MM/DD/YYYY):
^(0[1-9]|1[0-2])\/(0[1-9]|[12][0-9]|3[01])\/\d{4}$
IP Address:
^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$
Regex Syntax Guide
| Symbol | Meaning | Example |
|---|---|---|
| . | Any character | a.c matches "abc", "axc" |
| * | Zero or more | ab*c matches "ac", "abc", "abbc" |
| + | One or more | ab+c matches "abc", "abbc" |
| ? | Zero or one | ab?c matches "ac", "abc" |
| ^ | Start of string | ^abc matches "abc..." not "...abc" |
| $ | End of string | abc$ matches "...abc" not "abc..." |
| [abc] | Character class | [abc] matches "a", "b", or "c" |
| \d | Digit (0-9) | \d+ matches "123", "4567" |
| \w | Word character | \w+ matches "hello", "test123" |
| \s | Whitespace | \s+ matches spaces, tabs, newlines |
Regex Flags Explained
- Global (g): Find all matches, not just the first one
- Ignore Case (i): Case-insensitive matching
- Multiline (m): ^ and $ match line breaks
Common Use Cases
- Form Validation: Validate email, phone, and other inputs
- Data Extraction: Extract specific patterns from text
- Search & Replace: Find and replace text patterns
- Log Analysis: Parse log files for specific entries
- Data Cleaning: Remove or format unwanted characters
Tips for Better Regex
- Start simple and build complexity gradually
- Use online regex testers to validate patterns
- Comment complex regex patterns for future reference
- Consider performance - avoid excessive backtracking
- Test with various input scenarios
Last updated: 2025-11-07