Free Online Regex Tester & Debugger
Regular expressions (regex) are powerful tools for pattern matching and text manipulation. Our free regex tester allows you to write, test, and debug regular expressions in real-time with instant feedback on matches.
What is a Regular Expression?
A regular expression is a sequence of characters that defines a search pattern. Regex is used in programming for string matching, validation, search and replace operations, and text parsing. While powerful, regex syntax can be complex, making a testing tool essential for development.
Regex Flags Explained
- g (global): Find all matches rather than stopping after the first match.
- i (ignore case): Make the pattern case-insensitive.
- m (multiline): ^ and $ match the start/end of each line.
- s (dotAll): Allows . to match newline characters.
- u (unicode): Enable full Unicode support.
Common Regex Patterns
- Email:
[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,} - URL:
https?:\/\/[^\s]+ - Phone:
\d{3}[-.]?\d{3}[-.]?\d{4} - Date:
\d{4}-\d{2}-\d{2}
How to Use This Tool
- Enter your regex pattern in the pattern field.
- Specify any flags you need (g, i, m, etc.).
- Paste or type your test string.
- Click "Test Regex" to see all matches highlighted.
This tool processes everything locally in your browser, ensuring your test data remains private and secure.