Regex Tester
Test and debug regular expressions with live highlighting. Support for all regex flags. See match details and capture groups. Free online regex tester.
Free regex tester with live match highlighting. View capture groups, match counts, and test all regex flags (g, i, m, s, u) instantly in browser.
- ✓ Live highlighting of all matches as you type
- ✓ Support for global, case-insensitive, multiline, dotall, and unicode flags
- ✓ View capture groups and named groups in detail
- ✓ Real-time pattern validation with error feedback
- ✓ Works entirely in browser - no server processing
How to Test Regular Expressions
- 1 Enter your regex pattern in the pattern field
- 2 Select flags (g, i, m, s, u) as needed
- 3 Enter test string in the text area
- 4 View highlighted matches in real-time
- 5 Check capture groups and match details
Frequently Asked Questions
Is my code or data stored anywhere? ▼
No. All developer tools process data locally in your browser. Nothing is sent to any server or logged.
Can I use these tools offline? ▼
Yes! After the initial page load, most developer tools work without an internet connection.
Are there API limits? ▼
No limits. Since processing happens in your browser, you can use the tools as much as you need.
Is the output compatible with production use? ▼
Yes. Our tools produce standard-compliant output suitable for production environments.
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Last updated: January 15, 2026 · v2.1