Regex tester.

Write a regular expression and watch it match your text live — every hit highlighted, flags you can toggle, and all capture groups listed. JavaScript engine, no round-trips.

See the match, not just guess it

Regex is write-once, debug-forever — a pattern that looks right can quietly match too much or too little, and you only find out in production. Testing it against real strings with the matches highlighted turns that guesswork into something you can see. Watch the flags too: forgetting g or m is behind a surprising share of “why does this only match once” bugs.