The gradient flow provides a means to regularize UV-divergences in QFT. It is applicable both in lattice calculations as well as in perturbation theory, and thus forms an ideal framework for physical problems which involve short and long-distance effects. This talk introduces the concept of the gradient flow and its perturbative implementation. It then reports on a number of applications, among them the effective electroweak Hamiltonian as it is used to describe flavor physics observables such as K- or B-mixing and decays rates.