DrumCheck is a single HTML file that answers one question about a MIDI drum part: can a real human drummer play this — and if not, what do I change? Drop in a Standard MIDI File (or draw a groove), and a biomechanical model with two hands, two feet and a kit laid out in real-world centimetres checks every moment of the part. It reports impossibilities (three voices at once, a flam that needs both hands, an open and a closed hi-hat on the same tick, single-pedal kick runs beyond one foot, one-hand rolls beyond one wrist, stick travel that cannot arrive in time) and very-hard passages, each with the bar and beat, the limb involved, the physical number behind it (“96 cm in 67 ms, left hand”) and a plain-words suggestion for the fix. A tempo ceiling tells you the highest BPM at which the part is still playable. An animated top-down drummer performs the actual sticking the solver chose, so you see why a passage fails. You edit in place — notes, ghosts, accents, flams, drags, buzz rolls, triplet and 32nd lattices per beat — and every edit re-verdicts instantly. A feel engine (tight, laid-back, pushing, loose) humanises playback and export without ever changing a verdict. Export goes back to MIDI with real grace notes; projects save as .midicheck. It runs entirely in the browser, offline, with no account and no install.
