Circuit quantum electrodynamics (QED) is a very promising platform to simulate a quantum many-body Hamiltonian. In fact, many experimental results have already demonstrated how simple chemical processes can be studied with this approach. However, long-range interaction is a missing ingredient in the standard circuit QED toolbox. When a quantum emitter is coupled to a waveguide with an engineered dispersion relation, it becomes dressed with an exponentially decaying photonic cloud, emerging as an atom-photon bound state. The interaction of two atom- photon bound states not only goes beyond the simple nearest-neighbor (short) interaction but is intrinsically tunable by tuning the localization length of the photonic cloud. We realize this physics with a waveguide made of lumped-elements and explore new coupling regimes and geometry.