As electronic devices continue to evolve and shrink, so do their circuits and, ultimately, their components. This development has raised the demand for component miniaturization. 3D-Circuits or also called 3D-MID (three-dimensional mechatronic integrated devices) makes this possible. They allow for more compact designs while enhancing functional density. In this article, we take a closer look at 3D-MID technology, what it is, its many benefits, its applications, and a short overview about HARTING as a full-service provider.