Pure Data (Pd) is a visual programming language developed by Miller Puckette in the 1990s for creating interactive computer music and multimedia works.

While Puckette is the main author of the program, Pd is an open-source project with a large developer base working on new extensions.

Pd is natively designed to enable live collaboration across networks or the Internet, allowing musicians connected via LAN or even in disparate parts of the globe to create music together in real time.

In Pure Data and Max, functions or "objects" are linked or "patched" together in a graphical environment which models the flow of the control and audio.

Pd code forms the basis of David Zicarelli's MSP extensions to the Max language to do software audio processing.

[3] Like Max, Pd has a modular code base of externals or objects which are used as building blocks for programs written in the software.

Control messages and audio signals generally flow from the top of the screen to the bottom between "objects" connected via inlets and outlets.

In Puckette's words: Pd is designed to offer an extremely unstructured environment for describing data structures and their graphical appearance.

Further, Pd arrays and other entities are susceptible to namespace collisions because passing the patch instance ID is an extra step and is sometimes difficult to accomplish.