Build and test a regular expression against your own text, with live highlighting and a breakdown of every match and capture group. Runs entirely in your browser — nothing is uploaded.
\d digit · \w word character · \s whitespace · . any character · * 0+ · + 1+ · ? 0 or 1 · [abc] a set · (…) a capture group · | or · ^ start · $ end. The flags on the right: g finds all matches (not just the first), i ignores case, m makes ^/$ match each line, and s lets . match newlines. Everything runs in your browser using its built-in regular-expression engine — nothing is uploaded.