Circuit quantum electrodynamics studies the interactions between the microwave field of a cavity and an artificial atom. We develop a circuit quantum electrodynamics architecture for spin qubits by coupling an InAs nanowire double quantum dot to a high quality factor superconducting cavity. A charge trapped in the double quantum dot interacts with the electric field of the cavity, resulting in a large vacuum Rabi frequency of ~ 35 MHz. We drive single spin rotations using electric dipole spin resonance and demonstrate that photons trapped in the cavity are sensitive to single spin dynamics, allowing cavity readout of a spin qubit. The hybrid quantum system allows measurements of the spin lifetime and the observation of coherent spin rotations. Our results demonstrate that a spin-cavity coupling strength of 1 MHz is feasible, placing coherent coupling of spatially separated spin-qubits within reach of present technologies.