Regex tester
JavaScript flavor, live highlighting. Your text stays in the browser.
/ / g
JavaScript flavor, live highlighting. Your text stays in the browser.
Ready-made patterns with explanations, examples, and honest caveats:
Patterns execute with the browser's native RegExp engine — the exact engine your
JavaScript will use in production, not an emulation. Matches highlight live as you type, the
match list shows capture groups (named and positional), and the replace panel previews
String.replace output with $1-style references.
Like every tool on tarhun.dev, it is fully client-side: no account, no server round-trips, no stored history. Paste production logs without a second thought.
No. The pattern runs against your text with your browser’s own JavaScript regex engine, directly on this page. Nothing is transmitted or stored, so pasting logs or real data is safe.
JavaScript (ECMAScript) regular expressions — the flavor used in browsers and Node.js. It supports named groups, lookbehind, and Unicode property escapes with the u flag. PCRE-only syntax like atomic groups or possessive quantifiers is not available.
g finds all matches instead of the first; i ignores case; m makes ^ and $ match at line boundaries; s lets . match newlines; u enables full Unicode mode.