This tool uses JavaScript's built-in RegExp engine. It supports standard syntax including character classes, quantifiers, lookaheads, lookbehinds, and named groups.
g (global) finds all matches instead of stopping at the first. i (case-insensitive) ignores letter casing. m (multiline) makes ^ and $ match line boundaries. s (dotall) makes the dot (.) match newline characters.
No. All regex matching happens entirely in your browser. Nothing is sent to any server.