Regex Tester β live match highlighting
Test regular expressions with live match highlighting, in your browser.
π Runs entirely in your browser. Your input and output are never sent to a server or stored β fully private.
Matches: 0
About this tool
This regex tester lets you build a regular expression and see every match highlighted in your sample text as you type, so you can refine a pattern without guesswork. Toggle flags like global, case-insensitive and multiline, and check capture groups in the results. It all runs in your browser using the native JavaScript regex engine, so your patterns and text stay private.
Frequently asked questions
Which regex syntax does this use?
It uses the JavaScript (ECMAScript) regex flavor, the same one that runs in browsers and Node.js. Most patterns are portable, but features differ slightly from PCRE, Python or Java β for example lookbehind support and named groups depend on the engine.
What do the flags do?
Flags change how matching works: g (global) finds every match rather than just the first, i (insensitive) ignores letter case, m (multiline) makes ^ and $ match at each line, and s (dotall) lets the dot match newlines. You can combine them as needed.
Is my pattern or text sent anywhere?
No. Your pattern and test text are evaluated entirely in your browser and are never sent to a server, so you can safely test against real data.