The Xbox Development Kit, also known as the XDK for short, is a software development kit created by Microsoft. It was used to create software for the Xbox. It was used from between the years of 2000 and 2001.
The XDK included multiple tools to create Xbox software. The kit had a copy of Microsoft Visual Studio 2002 installed on to it. It also had the ability to record gameplay footage.
Some users on the website ASSEMBlergames have collected Xbox Dev Kit Discs that were used with the kit.
Overtime, the XDK would be used to homebrew older games and or games that came out on Sony's PlayStation 2. The XDK was used to write the code for the homebrewed games.