Axions can undergo efficient resonant conversion into low energy photons in the presence of of large background magnetic fields and dilute plasmas — environments which are frequently realized in the magnetospheres of neutron stars. Should axions contribute sizable to the dark matter density, the aforementioned conversion process can generate narrow spectral lines in the radio band. Alternatively, one can directly source a population of relativistic axions from the periodic collapse of vacuum gaps which arise e.g. near the magnetic poles of active neutron stars. In this talk I will discuss recent advancements in our understanding of these processes, and novel computational tools which are being developed to better characterize the radio signatures that ensure.