Which regex flavour is this?

JavaScript (ECMAScript), as used in browsers and Node.js. Most simple patterns work the same in other languages.

No. Everything happens in your browser and your inputs are saved only on this device.

Free Regex Tester & Explainer

Type a pattern and some text to see the matches and what the pattern means.

Test text

Invoices due 2026-10-15 and 2026-11-01.
Call 555-0123 before 2026-12-24.

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Which regex flavour is this?: JavaScript (ECMAScript), as used in browsers and Node.js. Most simple patterns work the same in other languages.
Is my data stored?: No. Everything happens in your browser and your inputs are saved only on this device.