The pursuit of reliable energy devices sealing solutions stands as a paramount engineering challenge for ensuring energy safety and dependability. This review focuses on an examination of recent scientific publications, primarily within the last decade, with a central aim to grasp and apply critical concepts relevant to the efficient design and specification of brazements for ceramic–metal active-brazed assemblies, emphasizing the sealing of energy devices. The goal is to establish robust and enduring joints capable of withstanding water-vapor and hydrogen environments. The review commences with a concise recapitulation of the fundamental principles of active brazing, followed by an in-depth exploration of material selection, illustrated using water-vapor-resistant sensors as illustrative examples. Furthermore, the review presents practical solutions for the sealing of energy devices while also scrutinizing the factors that exert significant influence on the deterioration of these active-brazed connections. Ultimately, the review culminates in a comprehensive discussion of emerging trends and developments in active brazing techniques for energy-related applications.