Novation Twitch
A mapping for the Novation Twitch will be included in Mixxx 2.1. You can use it now with Mixxx 2.0 by saving the following files to your controller mapping file locations#user controller mapping folder:
The mapping was made with the Mixco mapping framework and documentation for the mapping is available on the Mixco website.
This is the Mixxx Wiki - 
Mixxx is a free and open-source DJ software.
Manual
Hardware Compatibility
Reporting Bugs
Getting Involved
Contribution Guidelines
Coding Guidelines
Using Git
Developer Guide
Creating Skins
Contributing Mappings
Mixxx Controls
MIDI Scripting
Components JS
HID Scripting