Test JavaScript regular expressions with live match highlighting — runs in your browser
A regex tester lets you build and debug regular expressions interactively. You type a pattern, paste some sample text, and the tester instantly highlights every match — plus shows the capture groups, named groups, and the index of each hit. Instead of writing code, running it, and squinting at console output, you get immediate feedback as you tune the pattern.
Common use cases: building a validation pattern for emails, phone numbers, or postal codes; extracting structured data from logs or scraped text; debugging an existing regex that misbehaves on edge cases; learning regex syntax with quick experiments; building search-and-replace patterns for code editors and shell scripts.
g — global, find all matches instead of stopping at the first. i — ignore case. m — multiline, ^ and $ match line breaks. s — dotall, . also matches newlines. u — unicode, enables full Unicode support including emoji and surrogate pairs.
✅ Free — no signup, no spam
✅ 100% private — pattern and text never leave your browser
✅ Live highlighting of all matches
✅ Capture groups and named groups detailed
✅ Replace mode with $1, $2 backreferences
✅ Common pattern shortcuts (email, URL, phone, IP, date, hex)
JavaScript (ECMAScript). Same engine as Node.js and browsers. Patterns work mostly identically in Python, PHP, and Java with minor syntax differences.
g = global (all matches), i = case-insensitive, m = multiline, s = dotall (. matches newlines), u = unicode.
Each match is listed with its full text and every numbered or named capture group. Groups that did not participate appear as undefined.
No. Everything runs in your browser. Pattern and text never leave your device.
Some patterns can take exponential time. If your pattern hangs the browser, simplify it — nested quantifiers like (a+)+ are common culprits.
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