The non-perturbative S-Matrix Bootstrap aims at using the full content of the QFT constraints to determine physical observables. By combining those constraints with additional low-energy inputs it is possible to zoom in the space of EFT amplitudes. In this talk, I will explain how to interpolate from strong coupling to low-energy weak coupling in a toy example: the amplitude of a massive scalar in 4 dimensions. I will use this example to explain the methodology and discuss the physical interpretation. In the last part of the talk, I will add flavor and make a tentative contact with Higgs couplings.