GrooveForge is a portable MIDI keyboard studio for Android. Plug in a MIDI controller, pick a soundfont, and play. It began as a practice companion, light enough to carry on a phone or tablet, for rebuilding scales and muscle memory at a keyboard. It grew well beyond that, but it remains a tool for practising and playing, not a DAW. Rehearsals A band learning a tune together, without a studio. Everyone records their own part over a shared click, on their own phone, and the parts collect into one arrangement that every device holds a full copy of. Import a recording to play along to — MP3, FLAC and WAV everywhere, plus M4A, AAC and the sound of a video on Android. Tap the tempo, then drag a marker to the first downbeat so the grid lines up with the music. Every device delays sound on the way out and on the way in, which would push each take late. GrooveForge measures that delay on your device and shifts your take back by it, so what you played on the beat lands on the beat. Nothing is uploaded anywhere and no account is needed. Devices sync directly over the local network: scan a code once, then opening the same tune is enough. No internet needed, and without Wi-Fi one phone's hotspot is the whole network. Instruments GrooveForge Keyboard — soundfont synth (.sf2) with bank and patch selection and MIDI channel routing. Every slot is independent. Vocoder — mic-driven voice synthesis. Stylophone — monophonic metal-strip instrument. Theremin — touch pad with vertical pitch and horizontal volume. Drum Generator — beat patterns from bossa nova to metal, with human feel. Xen: microtonal scales Hold a note, tap a scale. The note you are holding becomes the tonic, the keyboard locks to the scale built on it, and — for scales that are not equal-tempered — the keys it uses are retuned to sound as the tradition intends. One keyboard, one gesture. 92 scales across eleven families: Western modes; Arabic and Turkish maqamat; Persian dastgah; Indian ragas in just intonati