Understanding the mechanisms of action of fundamental redox processes is of great interest for the development of more active catalysts and materials for energy storage and conversion devices. To gain more insight into those processes, spectroscopic techniques performed in situ and operando are widely used. In this work, we summarize recent advances in in situ and operando UV-vis, infrared (IR), Raman, X-ray absorption spectroscopy (XAS), and X-ray photoelectron spectroscopy (XPS) for energy storage and conversion applications. We then provide an outlook for the use of these techniques, focusing on improving their temporal and spatial resolution and combining multiple techniques in one experiment (i.e., using a multispectroscopy approach). Finally, we provide an overview of the advancements in the use of machine learning in this field and our perspective on its future applications.