Regex Tester

Highlight regular-expression matches and preview replacement text.

Make it work with your data.

Pattern (without / delimiters)

JavaScript flags

Text to search

Replacement text

HOW TO USE IT

Regex Tester

Enter a JavaScript regular expression and flags. Inspect each match and capture group, then review the replacement preview.

What to know

Matches use the browser’s JavaScript regex engine. The g flag finds all matches; without it replacement affects the first match. Replacement supports JavaScript tokens such as $& and $1. Expressions run in a worker and stop after two seconds so pathological patterns cannot freeze the page.

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