Regex tester
Write a regular expression and see the matches highlighted and the captured groups, in real time. In the browser, no data sent.
Genuinely free. No sign-up, no email, no limits, no cookies. We don't store the URL you analyse.
Type an expression and some text to see the matches.
What this tool cannot see
It uses JavaScript's regex engine and runs everything in your browser. Syntax may differ slightly from other languages (Python, PCRE): verify against your target runtime.
What it's for
Regular expressions are everywhere: input validation, data extraction, search and replace. They're easy to get wrong, and a tester that highlights matches and shows groups as you type is the fastest way to get them right without blind trial and error.
With the other tools: the text compare and the code formatter.
Frequently asked questions
›Which regular-expression engine does it use?
JavaScript's regex engine, the same one in your browser and in Node.js. Expressions that work here work in JavaScript/TypeScript code. Some syntax details may differ from other languages (Python, PCRE).
›What do the flags do?
They change behaviour: g finds all occurrences, i ignores case, m makes ^ and $ work per line, s lets the dot match newlines too, u enables Unicode mode, y (sticky) anchors the search to the current position.
›Are my regex and text sent anywhere?
No. Everything runs in your browser, on your text: nothing is sent to a server or stored.