The oxidation and corrosion of technical alloys is critical to their use, lifecycle and design of new materials. The oxidation cycle is complex and relies on transport through the alloy, the growing oxide, and surface reactions in a highly dynamic and heterogeneous material system. The oxide growth process has been studied for many decades and is well-understood, both on an empirical and mechanistic level. On the other hand, there are still significant, and impactful gaps in our understanding of the transition from alloy to oxide in the very early stages of the oxidation process. We will discuss the challenges and progress made in the study of the alloy surface reactions, and how they might (or might not) influence the oxidation process and therefore the performance of protective layers. Following a review of current work from the literature, we will focus on the Ni-Cr system including an illustration of the impact of minor alloying elements such as W, and Mo. This is an excellent model system, which is at the same time technologically relevant, and enabled us to probe the competition between transport and surface reactions. We will make an argument based on recent STM, XPS, AP-XPS and XPEEM studies why the surface chemistry, nucleation and surface diffusion can determine the outcome of  this process. We will address the challenges in achieving the “separation of variables” in this process by giving examples from our work on NiCr based superalloys.