Pure Data is described as 'Pd (aka Pure Data) is a real-time graphical programming environment for audio, video, and graphical processing. It is the third major branch of the family of patcher programming languages known as Max (Max/FTS, ISPW Max, Max/MSP, jMax, etc' and is a music production app in the audio & music category. There are more than 25 alternatives to Pure Data for a variety of platforms, including Windows, Mac, Linux, Web-based and Android apps. The best Pure Data alternative is VCV Rack, which is both free and Open Source. Other great apps like Pure Data are Max/MSP, plugdata, Vuo and SuperCollider.
Solid features for new folks as well as seasoned ones. Great help and reference documentation for objects and lots of integration possibilities including midi, Osc and tons of others. Vibrant user community.