The article discusses the transition from traditional membrane electrode assembly (MEA) electrolyzers to the innovative porous solid electrolyte (PSE) reactor design in the field of electrolysis. While MEA systems focus on molecular transformations at electrode surfaces for processes like water splitting to produce green hydrogen, the PSE reactor capitalizes on underutilized ionic transport. By introducing a porous, ionically conductive solid electrolyte between the anode and cathode, the PSE reactor enables the decoupling of cathodic and anodic reaction environments. This feature allows for independent pH optimization on each side of the reactor, beneficial for various electrochemical applications such as CO2 capture and water splitting. The article also highlights the historical background of three-chamber electrochemical reactors and the evolution of PSE technology, emphasizing the flexibility and efficiency it offers in electrolyzer systems. Despite the advancements, further improvements in mechanical integrity, kinetics, and mass transport are essential for enhancing operational performance and long-term stability. Overall, the research on PSE reactors showcases the potential to revolutionize electrolyzer systems by maximizing ionic transport, improving product collection, and enabling diverse electrochemical reactions.