Regex Tester
Test regular expressions against live text.
Runs 100% in your browser — nothing is uploaded
Test and debug regular expressions in your browser. Type a pattern, toggle flags, and see matches highlighted in your sample text in real time, with capture groups listed. A fast way to build and verify regex. Nothing is uploaded.
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Frequently asked questions
Which regex flavour is used?
JavaScript regular expressions, with support for the g, i, m, s, and u flags.
Does it show capture groups?
Yes — each match is listed with its capture groups so you can verify your pattern.
Is my text uploaded?
No. Matching runs entirely in your browser.
Why does my pattern show an error?
Invalid regex syntax is reported with the exact error message so you can fix it quickly.
Related tools
Handy companions people often use alongside Regex Tester.