Changelog

Highlights

• Four decks on one screen. EQ, filter, trim and a crossfader on every deck, running on a Web Audio engine. LESS view keeps it to two decks.
• Bring your rekordbox library. First run reads your tracks, playlists, beatgrids, cues, keys and waveforms. Open DJ never writes to rekordbox, and your library stays on your Mac.
• AutoPlay. Open DJ mixes the next track in for you, beat-matched with Beat Sync. Take over at any point.
• Move several knobs at once. Shift+click dials to select them, then scroll or drag to move them together. Drag up and down for one side and left and right for the other, to bring one track in while taking another out.
• Headphone cue on a single output. With one audio device, split cue puts the master in one ear and your cue in the other.
• See the vocals. A vocal lane shows where the singing sits, and synced lyrics run along the waveform for tracks that have them.
• Record your set. REC captures the master mix to a file.
• Scriptable. Every control has a local HTTP API and an opendj command-line tool, so you can drive the app from your own scripts.

Performance screen

• Four decks, the mixer and the browser stay usable in a 1280x720 window. PERF-UI-01.
• Controls that must feel instant (class A) have a stated latency budget and must not wait on a network round trip, and the app records the time from input to effect. LATENCY-01, LATENCY-03.
• Beat Sync never changes the master deck's tempo, and with the Beat Sync Max setting on, followers stay locked to the master's downbeat. LATENCY-05, DECKUX-14.
• Machine performance tiers scale the caches to your Mac. PERFMODE-01.
• Crash rescue from rolling on-disk snapshots of the decks. RESCUE-01.
• Cmd-Q asks before quitting and keeps audio playing until you confirm. INSTALL-21.

Mixer, stems and lyrics

• Stem mute and solo on every mixer channel strip. MIXUX-06.
• The STEM button turns a channel's EQ dials into stem levels. MIXUX-04.
• Per-stem mini-waveforms under each deck's waveform. DECKUX-19.
• Word-level lyrics as a lane on the waveform (LYR-03), and synced lyric lines beside the hot-cue bank (LYR-07).

Controllers

• The Mac app's window has no WebMIDI, so it never asks for MIDI access and says controllers are not supported there. CTRL-04.
• Source checkout in Chrome or Edge only, not the Mac app: a Pioneer DDJ-FLX4 device map, first hardware round Fri 18 Sep 2026. CTRL-01.

Library

• Point the app at a music folder with no rekordbox; tracks arrive labeled unanalyzed, with nothing guessed. SETUP-03.
• Tracks imported without vendor analysis are analyzed on import. PARITY-06.
• A scan that finds zero files where it found some fails loudly and changes nothing. LIBM-41.

Agents

• One typed command bus for UI, MIDI, keyboard and agents. AGENT-01.
• The opendj command line, inside the installed app. AGENT-05.
• An opendj mcp server in the app payload, with safety rails enforced server-side. AGENT-11.

Desktop app

• The launch dmg is signed with an Apple Developer ID and notarized by Apple. OPS-14.
• In-app updates, proven from 0.1.3 to 0.1.5. OPS-15.
• Every build reports its own identity, and shows a visible fault when it cannot. INSTALL-07.
• Google sign-in works in a packaged install with no shell setup. Sign-in is optional and the app works without it; it is required for the stems relay route and to enroll a machine in a CloudSync hub. AUTH-01.
• Apple silicon (arm64) only, stated wherever a download is described. INSTALL-05.
• No paid feature exists, so everything is available to everyone. ENT-04.

Known issues

• Stems use a lot of memory. Each track loaded with stems takes about 130 MB for every minute of audio. In a 30-minute AutoPlay test of this build on a 16 GB Mac, memory held steady between tracks at about 2.5 to 3 GB, and dropped to about 1.2 GB once every deck was ejected (about 0.4 GB at launch). Quitting Open DJ releases all of it. On a Mac with 8 GB, avoid loading stems on all four decks. The CHANGELOG in the source still describes the larger growth measured on the previous internal build, which this build fixes.
• AutoPlay can stop between tracks. With Beat Sync Max on, if Beat Sync cannot line the next track up with the playing one, the next track may load but not start, leaving silence. We have seen this when the two tempos are more than about 16% apart, and when the playing track has run past the end of its beat grid. Turn Beat Sync Max off to avoid it. A fix is coming in the next alpha.
• Setup can stay on "Import in progress" after a small import. Rarely, when a folder imports in a second or two, the setup window keeps saying "Import in progress" after the import has finished. Your music is already imported: choose "Use the app while this runs", or quit and reopen Open DJ. A fix is coming in the next alpha.
• The AutoPlay options menu is awkward to use. It closes if you move the pointer slowly from the AutoPlay button down to it, so move in one quick motion onto the option you want. Pressing Space there does not tick a box, so use the mouse. In the Light skin its text is hard to read; the Default and Gothic skins show it clearly. These are being fixed for the next alpha.
• >| (next-track loop) is experimental: the transition is abrupt and does not blend yet.
• Unfinished controls: a control with no real data source behind it is visible but inert, and its tooltip says so. Open DJ never shows invented data.

Not in this release

• Windows and Linux. This alpha is macOS on Apple silicon only.
• MIDI controllers in the Mac app. They work in Chrome or Edge only from a source checkout.
• Choosing audio outputs inside the app: the app plays to the macOS default output, so set it in macOS Sound settings (CUEOUT-14 is open).
• Effects beyond the channel filter, and a sampler: both are planned controls that show as not built.
• Making stems from the installed app. Prepared stems play; the code to produce them is in the app, but STEM-39 stays open until a signed build separates a track on a clean Mac, so today stems come from a source checkout. Word-level lyric timings also come from a source checkout.
• Live stems, separated in real time during playback, are not built.
• Paid features. There are none.
• In-app import from Serato, Traktor and djay. First-run import covers rekordbox and music folders; the other adapters run from the command line.