Test a regular expression against sample text, with matches highlighted live.
About this tool
Tests a regular expression against sample text with matches highlighted live as you type the pattern — using your browser's native regex engine, so behavior matches what your actual JavaScript code will do.
Frequently asked questions
Which regex flavor does this use?
JavaScript's native RegExp engine — the same one your browser or Node.js uses. Most syntax is shared with other regex flavors (PCRE, Python's re), but some features differ, so double-check flavor-specific syntax if you're writing the pattern for a different language.
Why do I need the "g" flag for this tool to highlight all matches?
Without the global flag, a regex only reports its first match. This tool applies it automatically even if you don't type it, specifically so every match gets highlighted rather than just the first one.