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Regex Tester
Write a pattern, set flags, and see matches highlighted in your test text as you type — with a list of every match, its position and its capture groups. Uses JavaScript regex syntax, the flavor used by browsers and Node.
Matches
Highlighted text
Quick syntax reminders
. any character · \d digit · \w word character · \s whitespace · + one or more · * zero or more · ? optional · [a-z] character class · (…) capture group · ^ / $ start / end. Flags: g find all, i ignore case, m multiline anchors, s dot matches newlines. Beware patterns that can match an empty string combined with greedy repeats on long text — they are the usual cause of "regex is slow" surprises.
Frequently Asked Questions
Which regex flavor is this?
JavaScript (ECMAScript) regex. PCRE (PHP) and Python differ in some advanced features like named groups syntax.
Why did it stop at 500 matches?
A safety cap so a loose pattern on a huge text cannot freeze your tab.
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