JavaScript RegExp Tester & Matcher

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Test JavaScript regular expressions and inspect matches and groups. Slow expressions stop after 500ms.

Ready

Input

RegExp Pattern (Without / delimiters)

Output

Regular expressions run in an isolated worker. If a pattern takes longer than 500ms, execution terminates to keep your tab responsive.

Which regex dialect is used?

Standard JavaScript (ECMAScript) RegExp as provided by your browser runtime.

What happens on catastrophic backtracking (ReDoS)?

Execution terminates after 500ms and displays a clear timeout notification.