Which regex flavour is used?

The tester uses JavaScript's built-in RegExp engine, which follows the ECMAScript specification. This matches the behaviour you get in Node.js, browsers, and most frontend frameworks.

Are capture groups shown?

Yes. Each match is listed with its position, and any capture groups within that match are shown as sub-items.

What flags are available?

g (global — find all matches), i (case-insensitive), m (multiline — ^ and $ match line boundaries), s (dotAll — . matches newlines), and u (Unicode mode) are all supported.

What does the live update mean?

As you type the pattern or the test text, matches are recalculated immediately without needing to click a button.

Regex Tester

The Regex Tester lets you write a regular expression and test it against sample text with live match highlighting. All JavaScript regex flags are supported (g, i, m, s, u). Matches are highlighted in the test text, captured groups are listed separately, and any regex syntax errors are displayed immediately.

Regex Pattern

gims

Test Text

Debug and validate regular expressions quickly without needing a code editor or a Node.js REPL.

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