N=4 SYM, sometimes described as the `harmonic oscillator' of 4d QFTs, provides a natural setting to explore the physics of defects in a relatively controlled environment. In this talk we will focus on codimension-1 features (boundaries, defects, interfaces) in a large-N regime where they are not small deformations of the ambient theory. We will discuss connections between field theory, holography and the matrix models emerging from supersymmetric localization, and recent results for correlation functions.
