We report the first application of Soft X-ray Photoelectron Spectroscopy (SXPS) to probe the bonding at epitaxial, bi-metallic interfaces with atomic-layer spatial selectivity. Specifically, we have measured the W(4f)7/2 levels of interfacial tungsten atoms for (1×1)Fe/W(110), (1×1)Ni/W(110), and (1×1)PtW(110). For clean W(110), the surface atoms exhibit a W(4f)7/2 peak at -320 meV binding energy with respect to the bulk W(4f)7/2 peak. Upon formation of the metallic overlayers, the interfacial tungsten atoms contribute W(4f)7/2 peaks at -225 meV (Fe/W), -140 meV (Ni/W), and +70 meV (Pt/W) with respect to the bulk W(4f)7/2 peak. The systematic reduction in the binding energy difference between interfacial and bulk tungsten atoms for Fe, Ni, and Pt correlates with increasing heats of adsorption on W(110), as determined by Temperature Programmed Desorption. This suggests that SXPS, in combination with first principles calculations and Born-Haber thermochemical cycle analyses, can be used as a non-destructive probe of bi-metallic interfacial bonding energies.