Rekordbox Performer

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

Signal path

MCP client → transition scheduler → loopMIDI → Rekordbox MIDI Learn

The DDJ-FLX4 remains connected as the Hardware Unlock device and manual control surface. 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

1. Install and start loopMIDI.

2. Create a port named Codex Rekordbox Performer and enable loopMIDI autostart.

3. Open Rekordbox 7 in Performance mode with the FLX4 connected.

4. Open Preferences → Controller → MIDI and select the virtual port.

5. Import mapping/Codex-Rekordbox-Performer.midi.csv. The fallback mapping/rekordbox-midi-learn.csv can be used for manual MIDI Learn.

6. Keep channel faders down and decks stopped during mapping.

7. Register rekordbox-performer as a stdio MCP server in your MCP client.

8. Call list_midi_outputs, connect_midi, and control_status.

9. 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 the same software control; mismatched hardware positions can cause value jumps.