Test regular expressions against sample text in your browser. This Regex Tester uses the JavaScript RegExp engine and is intended for practical pattern testing, examples, and debugging.
Test a regular expression
Enter a regex pattern, choose flags, and test it against sample text. JavaScript regex behavior can differ from Python, PCRE, Java, and other engines.
Examples: [0-9]+, \\d+, [A-Z][a-z]+, \\b\\w+@\\w+\\.com\\b
Matches
Match details
What this Regex Tester does
This Regex Tester helps you test JavaScript regular expressions against sample text. It shows matches, match positions, and capture groups when available.
How to test a regular expression
Enter a pattern, choose flags, paste sample text, and run the test. The tool creates a JavaScript RegExp object and applies it to the sample text.
Regex flags explained
- g: find all matches, not just the first match.
- i: ignore letter case.
- m: treat line starts and ends separately in multiline text.
Common regex examples
Digits: [0-9]+ or \d+
Email-like text: \b\w+@\w+\.com\b
Dates like 2026-08-05: \d{4}-\d{2}-\d{2}
Developer note
This MVP uses the browser JavaScript regex engine. Other programming languages can interpret some regex syntax differently.
FAQ
What regex engine does this use?
It uses the JavaScript RegExp engine available in the user’s browser.
Why does my regex work in one language but not another?
Regex syntax and features can vary by language and engine. This MVP is designed for JavaScript-style regex testing.
Can I test multiline text?
Yes. Paste multiline text and use the multiline flag if your pattern depends on line boundaries.