Online Regex Tester
Test regular expressions with live highlighting, flags, and replacement preview. 100% private, all processing in your browser
Frequently Asked Questions
Enter a pattern, toggle flags, and paste test text. The tool runs the JavaScript RegExp engine locally, highlights every match in place, lists each match with its index and captured groups, and previews any replacement.
No. All regex execution is done locally in your browser. Your text and patterns never leave your device, fully protecting your privacy.
The six standard JavaScript flags: g (global), i (ignore case), m (multiline), s (dotAll, dot matches newline), u (unicode), and y (sticky). Toggle any combination.
Validate input patterns like emails and phone numbers, build search-and-replace rules, parse logs, extract data from strings, and debug complex expressions step by step.
Completely free. This is a pure frontend online tool - no registration required, no payment needed, just open and use.
Yes. The tester uses your browser's native JavaScript RegExp engine, so results match what you will get in Node.js or the browser at runtime.
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