Regex Tester

Q: What regex engine does this use?

It uses the JavaScript RegExp engine with support for named capture groups, lookahead/lookbehind, and Unicode property escapes.

Real-time regular expression testing and debugging with live highlighting

Pattern

//gm

No matches

Test Text

Match Preview

Preview will appear here

💡 Real-time matching · Supports named groups (?<name>) · Data is processed locally in your browser

About This Tool

Regular expressions are powerful pattern-matching tools used for text validation, search, and replacement. This free online regex tester provides real-time matching with live highlighting — type your pattern and see results instantly, no button clicking needed.

Use this tool to debug complex regex patterns before deploying them in production code, learn how different regex flags (global, case-insensitive, multiline, dotall) affect matching, test named capture groups, and experiment with Unicode property escapes.

It supports all major regex flags (g, i, m, s, u, y), real-time match highlighting with color-coded captures, and handles everything from simple email validation to complex multiline patterns. The debounced input ensures smooth performance even with large test strings.

Frequently Asked Questions

Why is my regex not matching?

Check the flags: 'g' for global, 'i' for case-insensitive, 'm' for multiline. Common mistakes include missing the global flag or forgetting to escape special characters.

What regex engine does this use?

It uses the JavaScript RegExp engine, which supports most modern regex features including named capture groups, lookahead/lookbehind, and Unicode property escapes.

Is this safe for sensitive data?

Yes. All regex matching is done locally in your browser. Your patterns and test strings never leave your device.

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