Developer Tool
🔍 Regex Tester
Test regular expressions with live match highlighting, capture groups, and flags. Uses JavaScript's native RegExp engine — everything runs in your browser.
⚡ Common Patterns (click to load)
📖 Regex Cheat Sheet
. — any char except newline\d — digit [0-9]\w — word char [A-Za-z0-9_]\s — whitespace[abc] — a, b, or c[^abc] — not a, b, or c* — 0 or more+ — 1 or more? — 0 or 1{n} — exactly n{n,m} — between n and m*? — lazy match^ — start of string/line$ — end of string/line\b — word boundary\B — non-word boundary(...) — capture group(?:...) — non-capturing(?=...) — lookahead(?!...) — negative lookahead| — alternation (or)❓ Frequently Asked Questions
What is a regex tester?
A regex tester is a tool that lets you write a regular expression and instantly see which parts of a text string match. It highlights matches and shows capture groups in real time.
What regex flavor is supported?
This tester uses JavaScript's native RegExp engine, which is compatible with most modern regex flavors and supported in all browsers and Node.js.
What do the regex flags mean?
g = global (find all matches), i = case insensitive, m = multiline, s = dotall (. matches newlines), u = unicode, y = sticky (match from lastIndex only).
Is my data sent to a server?
No. All regex matching happens locally in your browser. Your patterns and text never leave your device. No tracking, no ads.
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