iOS · Feature-complete · Coming with iOS 26.5
DrumFillGenerator picks from a bank of ~200 hand-transcribed linear fills — or generates a fresh one when nothing fits your grid. Play along with real-time rhythmic tracking via mic or MIDI, read each fill on a color-coded step grid or a classical staff, and practice with humanized playback feel. Sample-accurate, zero-latency, built for the music stand.
What it does
A generator, trainer and real-time tracking tool with a generous free tier: ~200 curated fills, mic & MIDI tracking, humanized playback, a rock-solid audio engine, and two ways to read every pattern.
A professionally-authored bank of linear fills across genres — 4/4 and 3/4 across quarter, eighth, sixteenth and triplet subdivisions. All curated fills are free. The library updates remotely without an app release.
Real-time onset detection via mic (practice pad) or MIDI (e-drum kit). Hit timing is scored against the grid — green for on-time, amber for early, red for late. Visual feedback per step, timeline markers, and loop cycle history.
Robot, Tight, Natural, or Loose — inject micro-timing slop and velocity swing into audio playback only. Visuals and metronome stay on the mathematical grid. Responds live mid-playback, no restart needed.
Read every fill as a chunky color-coded step grid (free) or a traditional 5-line drum staff (premium) — both render from the same source. Tap a step to cue, drag to scrub or seek live.
Bookmark fills you love with a single tap, rename and organize them. Track your practice in the Progress Hub — see your timing accuracy improve across sessions.
AVAudioEngine with per-instrument voice pooling, three velocity tiers, ergonomic hand orchestration via DP-based spatial search, metronome, and a prefill groove that wraps your fill in full-song context.
Multi-bar fills with mixed subdivision support. Select instruments, time signature, and feel — the engine finds a curated match or generates one with ergonomic hand orchestration that minimizes hand travel.
An always-visible indicator during active playback via Dynamic Island and the Lock Screen — see your fill status even when the app is in the background.
A synced click with accent on the downbeat, prefill/afterfill groove for full-song context, per-instrument gain control, rudiment detection, and tap-to-cue transport. Built for serious practice.
How it works
Pick a time signature (4/4 or 3/4), subdivisions from quarters to triplets (multi-select supported), 1–4 bars, and toggle which of the six voices play.
A matching curated fill is preferred from the ~200 library. When none fits your instrument pool, the linear randomizer builds one with ergonomic hand orchestration — minimizing hand travel via DP-based spatial search.
Loop at any tempo with the click on, toggle the prefill groove for full-song context, and dial in your Playback Feel — from robotic to loose. Flip between grid and notation, tap to cue, drag to scrub.
Connect headphones (mic mode) or a MIDI e-kit, enable tracking, and play along. Each hit is scored green/amber/red against the grid. Review per-cycle results, save favorites, and watch your timing improve in the Progress Hub.
Under the hood
Be first on the kit
One email when DrumFillGenerator hits the App Store. No spam, no drip campaign — just the launch.