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Regex Tester

Test a regular expression against sample text and inspect every match.

Pattern

Test text

Matches: —

How to use the Regex Tester

  1. Type your regular expression in the pattern box.
  2. Toggle the flags you need.
  3. Paste test text and read the highlighted matches and groups below.

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Frequently Asked Questions

Common questions about the free online regex tester.

It uses the browser's native JavaScript regular expressions, which follow the ECMAScript standard.
i ignores case, m makes anchors work per line, s lets the dot match newlines, and u enables full Unicode mode.
The most common causes are a missing escape for special characters, or anchors that do not match anywhere in your text.
Yes, since the browser engine supports them. They appear in the group list for each match.
It stops after 5000 matches and caps the loop, but a pathological pattern can still be slow, so keep test text small while experimenting.
No. Matching happens entirely in your browser, so your patterns and text stay private.
Yes. The tester is fully responsive and works on desktop, tablet and phone.
Yes, it is completely free with no account required.

Last updated: October 10, 2026