Why did my test stop with a timeout warning?

To protect your browser tab, matching is capped at a short time budget. A timeout usually means the pattern has exponential backtracking on this input — try narrowing the pattern (e.g. avoid nested quantifiers like (a+)+).

Regex Tester

Test regular expressions against sample text with live matches.

Processed locally in your browser. Nothing you enter is uploaded or stored.

//g

Overview

Test a regular expression against sample text and see every match, capture group and flag behavior highlighted live.

How to use it

1Enter a pattern and choose flags (g, i, m, s).
2Paste test text.
3Matches are highlighted inline; capture groups are listed below.

Tips

A pattern that runs for a long time on certain input may indicate catastrophic backtracking (ReDoS) — this tool applies a execution time guard and will stop runaway patterns.

Frequently asked questions

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