The gauge/gravity duality, combined with information from lattice QCD, nuclear theory, and perturbative QCD, can be used to constrain the equation of state of hot and dense QCD. I discuss an approach based on the holographic V-QCD model. I start by reviewing the results from the construction of the V-QCD baryon as a soliton of the gauge fields in the model. Then I discuss implementing nuclear matter in the model by using a homogeneous approach. The model predicts a strongly first order phase transition from nuclear to quark matter with a critical endpoint. By using the model in state-of-the-art simulations of neutron star binaries with parameters consistent with GW170817, I study the formation of quark matter during the merger process.Comme...