It'd be awesome (and crazy, but more awesome) if MIDI would be a valid input and output.
The possibilities for those having a MIDI keyboard would be endless, starting with ditching the annoying GarageRemote to proper scripting of all the possible musical tools.
Please make it happen!
Elaborating on the "output": it'd be nice to be able to re-map some MIDI commands and fun to do MIDI actions with trackpad.
Midi Input will be added very soon. Midi output should probably also be doable, but I'll need to look into this.
Still patiently waiting for MIDI support......
Yes, patiently waiting for it too...
Some things take time 
funny enough I managed to ditch the "proper" midi keyboard since opening this request and my current one has a very limited set of midi messages it can send. Still excited about this feature, though.
It's 2019 and we still have yet to see this feature...
Stay calm, it'll come out with MIDI 2.0
hehe sorry, I have midi support working here, but can't release it until the new UI is finished. Currently completing some freelance projects until mid February, after that I'll focus on getting the new UI released.
Thanks for the update Andreas, I know it will be worth the wait! I can wait a few more months, trying really hard not to purchase Keyboard Maestro just for MIDI support. 
Soo it took way longer than anticipated (because I needed to make the new UI more stable before adding MIDI support, also various other topics got in the way), but the latest alpha (v2.809) includes first basic support that will now be completed during the next 1-2 weeks.
Currently the UI and functionality is still very limited and only targetet at early testers / advanced users:
Basically you open the "MIDI Event Viewer" to figure out which are the correct command and control values you want to target, then you configure your trigger to match that. For example in the screenshot above I have configured a trigger that executes when the Note On Command (159) is received AND the note/control with number 40 is also on/active.
If you assign the predefined action "Run Apple Script (async in background)", the Apple Script can receive the current value/velocity/whatever by using a script like this:
on bttMIDIValueChanged(midiValue)
#example to change system volume, max midi value is 127:
set volume output volume (midiValue / 127) * 100
end bttMIDIValueChanged
I'm not at all a MIDI expert and only own one device, so any suggestions would be great. The UI to configure the triggers will be improved and things like "repeat" will be activated over the next 1-2 weeks. MIDI Output will be added after that.
Hi Andreas, the MIDI input has proved very helpful in my setup! Any chance of seeing MIDI output soon? 
+1 for output. I have a MIDI controller that I use BTT to convert to keystrokes. With MIDI output I could control LEDs in that process. I tried to look at sending the MIDI with AppleScript but didn't find a good solution.
+1 UP for midi output.
Some software I use, uses midi messages for changing presets. It would be cool to be able to use F14 to F19 on the apple extended keyboard to do that.
+1 to midi output!
I am a DAW user and really into using touchbar as a midi controller for live performances or custom midi messages for faster music making.
At the moment there is the only app that allows to have midi controls (it called midi touchbar) and it is not even close to BTT.
I even registered just to write this request, dreaming it almost about the year
BTT is versatile and flexible, it will be the best midi touchbar on the market.
Thank you for existing! Have a great everything!
So maybe it's the time to implement MIDI out using chat GPT help? 
It would be necessary to add a "Channel" field, where we could select from channel 1 to 16, and channel Omni.
Another nice addition would be to add software MIDI buses as inputs for MIDI Triggers. Right now, only MIDI inputs from physical controllers or Apple's IAC Driver are available, but I have some music applications that use virtual MIDI buses, which show up in all my other apps as well as my MIDI Monitor, but not BTT.
Still hope that it could happen 
hope dies last