Abstract: It has been proposed that heterostructures formed by semiconductor quantum wells with strong spin-orbit coupling, and superconductors, can be designed to realize planar Josephson junctions that can be driven into a superconducting topological state. In addition, the discovery of materials with non-trivial topological properties has led to the realization of novel junctions with anomalous, and still not well understood, properties. In this talk I will discuss how the response of a Josephson junction under microwave radiation can be used to extract detailed information on the microscopic electronic properties of the junction. I will present results specific for the case of planar Al/InAs Joesphson junctions, and junctions based on Dirac semimetals. For Al/InAs junctions I will show the importance of combining signatures in the microwave response with other additional correlated signatures to make claims about the topological character of a Josephson junction. For junctions based on Dirac semimetals I will show how qualitative features of the junctions' response under microwave radiation are strong signatures of the presence of a Leggett mode in the superconducting Dirac semimetal.