Skip to content
Trigger events and automate shows in response to events on Pioneer CDJs
Branch: master
Clone or download
brunchboy Auto-open expression editor for Custom track enabled filter.
The other menus had this hooked up correctly, but this one was
Latest commit b40f237 May 20, 2019
Type Name Latest commit message Commit time
Failed to load latest commit information.
.github Remove redundancy, improve wording. Sep 14, 2018
doc Document new "Same" default for Started Late message. May 18, 2019
resources Make build work for new clones of the repository. Mar 9, 2019
src/beat_link_trigger Auto-open expression editor for Custom track enabled filter. May 19, 2019
test/beat_link_trigger Created proof-of-concept project. May 13, 2016
.gitignore Switch to using custom Deep Symmetry Antora UI. Apr 21, 2019 Auto-open expression editor for Custom track enabled filter. May 19, 2019 Create Jul 6, 2017
LICENSE Created proof-of-concept project. May 13, 2016 Update landing pages to link to netlify hosted user guide. May 16, 2019
project.clj Update versioning helper plugin. May 15, 2019


Gitter Beat Link

An application to trigger MIDI events when CDJs start playing tracks, reach particular beats, or whatever else you can think of. Built using beat-link. There is more description and a video in a DJ TechTools article, too!



Download the latest disk image (.dmg) installer for the Mac, .msi installer for 64-bit Windows, or executable .jar file for other platforms, from the releases page and double-click it to run it. If that doesn’t work, see below.


A trigger window will open, in which you can choose the players you want to watch, the kind of MIDI message to send when they start and stop, and when the triggers are enabled:

Trigger window

There is also an interface for monitoring the status of each player found on the network, which you can access by choosing Show Player Status in the Network menu:

Player Status window

And starting with version 0.5.0, there is a Show interface with which you can paint cues on track beat grids, to automate away the complexities of manually managing triggers.

Show interface snippet

Going Further

This page is just a quick introduction! Please see the the full 📓 user guide for many more details, including:

  • How to configure Triggers
  • How to use Expressions
  • Working with title/artist metadata
  • Working with Ableton Link
  • Integration examples

And much more... and hopefully you will soon be coming up with interesting integration projects of your own.

You can also find user-contributed examples and resources on the project Wiki. Once you have come up with your own great ways to use Beat Link Trigger, please add a page or two the Wiki to share them with others!


First of all, we would love to hear from you! We have no way of knowing who has discovered, explored, downloaded and tried Beat Link Trigger. So if you have, please write a quick note on the Gitter chat room to let us know! Even if it is only to explain why it didn’t quite work for you.

If you run into specific problems or have ideas of ways Beat Link Trigger could be better, you can also open an Issue.

And if you think you've come up with new or better way to do something, terrific! Please take a look at our guidelines for contributing and we can't wait to hear from you!

Please be mindful of our Code of Conduct to make sure everyone feels welcome in the community.


Beat Link Trigger is, and will remain, completely free and open-source. If it has helped you, taught you something, or pleased you, let us know and share some of your discoveries and code as described above. If you’d like to financially support its ongoing development, you are welcome (but by no means obligated) to donate to offset the hundreds of hours of research, development, and writing that have already been invested. Or perhaps to facilitate future efforts, tools, toys, and time to explore.

Donate using Liberapay using Liberapay, or Donate using PayPal

If enough people jump on board, we may even be able to get a newer CDJ to experiment with, although that’s an unlikely stretch goal. 😀


This is in no way a sanctioned implementation of the protocols. It should be clear, but:

⚠️ Use at your own risk! For example, there are reports that the XDJ-RX crashes when BLT starts, so don’t use it with one on your network. As Pioneer themselves explain, the XDJ-RX does not actually implement the protocol:

“The LINK on the RX is ONLY for linking to rekordbox on your computer or a router with WiFi to connect rekordbox mobile. It can not exchange LINK data with other CDJs or DJMs.”

While these techniques appear to work for us so far, there are many gaps in our knowledge, and things could change at any time with new releases of hardware or even firmware updates from Pioneer.

You should also not expect to be able to run Beat Link Trigger, or any project like it, on the same machine that you are running rekordbox, because they will compete over access to network ports.

Beat Link Trigger seems to work great with CDJ-2000 Nexus gear, and works fairly well (with less information available) with older CDJ-2000s. It has also been reported to work with XDJ-1000 gear. If you can try it with anything else, please let us know what you learn in the Gitter chat room, or if you have worked out actionable details about something that could be improved, open an Issue or submit a pull request so we can all improve our understanding together.

If something isn’t working with your hardware and you don’t yet know the details why, but are willing to learn a little and help figure it out, look at the dysentery project, which is where we are organizing the research tools and results which made programs like Beat Link Trigger possible.

Startup Issues

If you downloaded the .jar version and double-clicking doesn’t open up the application, make sure you have a recent Java SE runtime environment installed, and try running it from the command line:

java -jar beat-link-trigger.jar

If that does not work, at least you will be able to see a detailed report of what went wrong, which can help you troubleshoot the issue.

Font-Related Bugs

If you see a long exception stack trace similar to the one in this discussion and you have your computer language set to one that uses an alphabet which is substantially different from English, you may be encountering what seems to be a bug in the GUI library (or maybe even in Java itself). Try setting your system language to US English, and see if that at least lets you run the program.

Mac Trust Confirmation

If you are on a Mac, your best option nowadays is to download the disk image installer. It contains Beat Link Trigger packaged as a native Mac application, with an embedded Java 11 runtime, so you don’t need to worry about installing or managing Java if you don’t use it for other purposes. It is code-signed by Deep Symmetry, so your Mac should be happy to install and run it without complaint.

Installer window

If you already have your own Java runtime installed and want to use it, you can instead download the smaller executable .jar file, but then the first time you try to launch the downloaded jar file by double-clicking it you will see an error like this because it is not a Mac-specific application:

Unsigned jar

You can fix that by control-clicking on the Jar and choosing “Open” at the top of the contextual menu that pops up. You will be asked to confirm that you really want to run it. Click the “Open” button in that confirmation dialog, and from then on, you will be able to run that copy by just double-clicking it.

Confirmation dialog

You will need to repeat this process for each version that you download.


Deep Symmetry

Copyright © 2016–2019 Deep Symmetry, LLC

Distributed under the Eclipse Public License 1.0, the same as Clojure. By using this software in any fashion, you are agreeing to be bound by the terms of this license. You must not remove this notice, or any other, from this software.

Library Licenses

Remote Tea, used for communicating with the NFSv2 servers on players, is licensed under the GNU Library General Public License, version 2.

The Kaitai Struct Java runtime, used for parsing rekordbox exports and media analysis files, is licensed under the MIT License.

You can’t perform that action at this time.