Circuit quantum electrodynamics is a currently very active field of research. Since the discoveries that an artificial spin, the so-called qubit, can be implemented using a superconducting non-linear circuit and can coherently interact with the electromagnetic field at the single-photon level, it has gathered strong interest for its potential for quantum computing but also for its ability to create, manipulate and detect microwave states with an exquisite precision. In this talk, I will present how the tools and concepts developed for quantum circuits can be used to interface microwaves and phonons, and microwaves and spins, with applications to quantum sensing.