Regex Tester
Test and debug regular expressions in real-time. See highlighted matches, captured groups, and use replace mode. Includes a library of common patterns.
How to Use This Regex Tester
Enter your regex pattern in the pattern field and your test text in the text area below. Matches are highlighted in real-time as you type. Toggle flags (g, i, m, s) to modify matching behavior. Use Replace mode to test string replacements with capture group references ($1, $2). Click any common pattern button to quickly load frequently used regex patterns.
Regex Flags
g (global) matches all occurrences, not just the first. i (case-insensitive) ignores letter case. m (multiline) makes ^ and $ match line boundaries. s (dotAll) makes . match newline characters.
Frequently Asked Questions
Is my data safe?
Yes. All regex matching happens in your browser. No data is sent to any server.
Which regex engine is used?
This tool uses JavaScript's built-in RegExp engine, which follows the ECMAScript specification. Syntax and behavior match what you would get in Node.js or any modern browser.