Rekordbox Performer

Safety-first live Rekordbox control over a dedicated virtual MIDI port.

[!WARNING]This is an experimental prototype for supervised performance. Keep aphysical controller available and test mappings with channel faders down.

Signal path

MCP client → transition scheduler → loopMIDI → Rekordbox MIDI Learn

The DDJ-FLX4 remains connected as the Hardware Unlock device and manual controlsurface. This server does not modify the Rekordbox database or process audio.

Requirements

Windows with Rekordbox 7 in Performance mode
Python 3.12 or newer
A virtual MIDI port such as loopMIDI
A Rekordbox-compatible controller for Hardware Unlock when required

Install

py -3.12 -m venv .venv
.\.venv\Scripts\python.exe -m pip install -e .

Setup

Install and start loopMIDI.
Create a port named Codex Rekordbox Performer and enable loopMIDI autostart.
Open Rekordbox 7 in Performance mode with the FLX4 connected.
Open Preferences → Controller → MIDI and select the virtual port.
Import mapping/Codex-Rekordbox-Performer.midi.csv. The fallbackmapping/rekordbox-midi-learn.csv can be used for manual MIDI Learn.
Keep channel faders down and decks stopped during mapping.
Register rekordbox-performer as a stdio MCP server in your MCP client.
Call list_midi_outputs, connect_midi, and control_status.
Preview a transition, arm control, then perform it.

The dedicated mapping does not replace the DDJ-FLX4 factory mapping.

Safety model

Live messages are rejected until control is armed.
Arming expires automatically after at most 30 minutes.
Transition plans default to dry-run preview.
All scheduled events run against a local monotonic clock.
Emergency stop cancels pending automation and disarms without moving controls.
The physical FLX4 remains the manual override.

Do not move a physical FLX4 continuous control while automation is moving thesame software control; mismatched hardware positions can cause value jumps.

Rekordbox Performer