Regex Tester & Debugger
Test and debug regular expressions online with highlighting
"hello@example.com"at index 14"hello"$2: "example.com""support@devtoolbelt.com"at index 35"support"$2: "devtoolbelt.com"About Regex Tester & Debugger
Test and debug regular expressions in real-time with instant match highlighting. See all matches, capture groups, and match positions. Supports JavaScript regex flags (global, case-insensitive, multiline, dotall). Essential for building and testing patterns for form validation, data parsing, and text processing.
Use Cases
- Testing email validation patterns
- Debugging data extraction regex for web scraping
- Building search patterns for log file analysis
- Validating form input patterns before implementing
Frequently Asked Questions
What regex flavor does this use?
This tool uses JavaScript's native RegExp engine, which is the same engine used in Node.js and all modern browsers.
What are regex flags?
Flags modify how the pattern matches: g (global - find all matches), i (case-insensitive), m (multiline - ^ and $ match line boundaries), s (dotall - . matches newlines).
What are capture groups?
Parentheses () in regex create capture groups that extract specific parts of a match. For example, (\w+)@(\w+) captures the username and domain in an email.
Is my data processed locally?
Yes. All regex testing happens in your browser using JavaScript. No data is sent to any server.