The existence of the Standard Model (SM) Higgs implies that a gravitational wave (GW) background is generated by the decay products of the Higgs, soon after the end of inflation. Theoretically, all Yukawa and SU(2)L gauge couplings of the SM are imprinted as features in the GW spectrum. However, in practice, the signal from the most strongly coupled species dominate, rendering inaccesible the information on the other species. This background could be used for inferring properties of particle physics, including beyond the SM, at energies way above the reach of LHC. To measure this background, however, new high frequency GW detection technology is required.