Based on 2306.05551 with Ankur and D. Carmi. Studying QFT in AdS allows to translate phenomena in massive QFT in the bulk to properties of the boundary conformal correlators. I will illustrate this in the example of a strongly coupled gauge theory, namely scalar QED in dimension D<4. The tool that I will use to compute is the large N expansion, where N is the number of flavors. I will show that the four-point function of the charged operator dual to the scalar electrons can be computed exactly in the coupling at leading order at large N, both in the Coulomb and in the Higgs phase, and explain its salient properties. Finally I will discuss an IR divergence present in integer dimension D=3 that signals the breaking of the AdS isometries due to a boundary running coupling.