In summary, combination of ex situ and operando spectroelectrochemical techniques allows us to disentangle the structural and reaction kinetics of our catalysts during the electrolysis process. We demonstrate that significant structural rearrangements of the catalysts induced by pH or applied potentials are the key to initiate the HER/OER in different media. At the same time, the in situ formed catalytically active species often display quite complex features of their local geometry around the metal centers and display a kinetic behavior along with the applied potentials or the running reactions. This behaviour eludes conventional ex situ characterizations in the post-catalytic samples. Caution needs to be exercised when unveiling the reaction kinetics of the catalysts in different media, where a precise identification of the nature of catalytically active sites and species is necessary.