AI hands you a pattern. This shows you what it actually matches — highlighted, live, on your text.
Everyone can get a regular expression these days — an AI will hand you one in a second. The problem is the one it hands you looks right and quietly matches the wrong thing. This regex tester closes that gap: type a pattern and every match lights up in your own text as you type, with a live count and the contents of each capture group. You see what it really does before it reaches production.
The panel underneath drops in tested patterns for the things people actually validate — email, URL, IPv4, phone number, ISO date, hex colour, whitespace, digits — plus the syntax reminders everyone re-Googles: \d digit, \w word char, \b boundary, + one or more, * zero or more, ? optional, () capture group, [] character class.
This is the JavaScript (ECMAScript) flavour, because it runs in your browser — the vast majority of patterns behave identically in Python or PCRE, but lookbehind and named-group syntax can differ, so we say so rather than pretend. And because a careless pattern can backtrack catastrophically and freeze a tab, matching runs inside a Web Worker with a 1-second timeout: a runaway regex gets stopped, not your browser. Your pattern and text never leave the page.
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