The BPM readout is a guess. It's detected from the audio and it's usually right on four-to-the-floor music, but it can miss — that's why TAP is next to it, and why the beat lamps and drift meter are labelled estimates. Your ears outrank every number on this page. That's not a limitation, that's the entire method.
Pitch changes the key, exactly like a turntable — there's no keylock here yet. Nudge fixes a beat that's drifted now; pitch fixes the speed for good. If those two sentences are new to you, read Beatmatch By Ear in 10 Minutes first.
Recording captures exactly what leaves the crossfader, in your browser, and downloads as a file. Nothing is stored anywhere else.
Want the trainer version with built-in beats (nothing to load)? That's the Mix Simulator. This page is the next step: the same skill on your record box.
The bit that actually moves you on is someone stood next to you saying “that’s why it slid.” I teach one to one in King’s Lynn on the real thing — Pioneer CDJ-3000X, a DJM-V10-LF and Technics 1210s — not a controller you’ll never see in a booth.
Not near Norfolk? Nothing here goes behind a paywall — carry on through the free lessons.