Starting today, the company has made the game unavailable for download on both platforms; online services will be shut down after August 12. Users must download and save all Project Spark content they want to access by that time.
Project Spark was much-feted by Microsoft in the early days of the Xbox One, and enabled creators to develop their own games using game objects and logic.
"When Project Spark transitioned away from active development last fall, many of our team members moved to other projects within Microsoft Studios. While this means there have been no layoffs at Microsoft, it also means it’s simply no longer feasible to continue the behind-the-scenes work involved with keeping Project Spark up and running with meaningful updates and bug fixes, so we have come to this hard decision," wrote community manager Thomas Gratz, in the blog post announcing the shutdown.
Those who purhcased and activated a retail copy after October 5 of last year will be granted a store credit in their Xbox Live account.
For a window into what made this ambitious project tick, watch this 2013 GDC Next talk by Microsoft's Soren Hannibal.