Developer

Regex Tester

Test regular expressions with live matching

//g

Hello World, this is a Regex Tester. Try matching Capitalized Words like Paris or London.

Matches: 9Characters matched: 51

“Hello” @0“World” @6“Regex” @23“Tester” @29“Try” @37“Capitalized” @50“Words” @62“Paris” @73“London” @82

About Regex Tester

The Regex Tester lets you write and test regular expressions with live matching and highlighting. It runs entirely in your browser with no data stored on any server. This free tool is perfect for developers building and debugging regex patterns for validation, parsing, or text processing.

Frequently Asked Questions

How do I test a regular expression?

Enter your regex pattern in the pattern field and your test text in the text area. The tool will instantly highlight all matches and display capture groups. You can use flags like global, case-insensitive, and multiline.

Is my regex or test data stored?

No, everything runs in your browser. Your regular expressions and test text are never sent to any server or stored anywhere. You can safely test patterns against sensitive data without privacy concerns.

What regex features are supported?

The tool supports the full JavaScript regular expression syntax, including capture groups, lookaheads, lookbehinds, character classes, quantifiers, and all standard flags. It highlights matches in real time and shows capture group contents for each match.