Which regex flavor does this use?

JavaScript (ECMAScript) regular expressions, the same engine used in Node.js and every browser. It supports all standard flags — g, i, m, s, u and y — plus numbered and named capture groups.

Is my pattern or text uploaded?

No. The matching runs in your browser, so your pattern and test text stay on your device. Nothing is sent to a server.

Regex Tester

Test regular expressions live with match highlighting, capture groups and every JavaScript flag. Your pattern and text never leave your browser.

Regular expression

Test string

Contact alice@example.com or bob@mail.org for details.

Highlighted matches

See exactly what your regex matches

Regular expressions are powerful but easy to get subtly wrong. Type a pattern and some sample text, and every match lights up instantly in the string below — so you can tell at a glance whether your pattern is too greedy, missing edge cases, or catching more than you intended. Toggle flags on and off to watch the behavior change in real time.

Capture groups, positions and flags

Each match is listed with its character position and every capture group, including named groups like (?<year>\d{4}). All six JavaScript flags are available: g global, i ignore-case, m multiline, s dotall, u unicode and y sticky.

Private by design. Matching runs in your browser — your pattern and test data stay local. Nothing is uploaded.

Frequently asked questions

Which regex flavor is this?

JavaScript (ECMAScript) — the same engine as Node and browsers, with all standard flags and capture groups.

Does it show capture groups?

Yes — every match lists its position and all groups, numbered and named.

Is my data uploaded?

No — matching is entirely local to your browser.

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