Matchsmith

Matchsmith teaches regular expressions the way they finally stick: by writing real patterns and watching them match real text, live. Type a pattern and it highlights every match in the test string as you type, so you get instant feedback on what your regex is catching — and missing — instead of guessing. It's a proper course, not just a tester. Structured challenges climb from literals and character classes through quantifiers, groups, alternation, and lookarounds, each with a clear task. Matchsmith checks your pattern against should-match and shouldn't-match cases, so a solution has to be genuinely correct — get it close and the failing cases show you exactly what to fix. A sandbox lets you test any pattern against any text, with a library of ready-made patterns — emails, dates, IPs — to load and learn from, plus a reference for when you forget what \b or (?=) does. Progress, saved patterns, and a practice streak keep you coming back. Everything runs on your device: no account, no connection, no ads. Just patterns, matches, and regex that finally makes sense.