Nanoporous metallic foams (NMFs) are usually 3D structures of pores and interconnected nano-ramified walls that present porosities higher than 50% as well as a wide pore size distribution. These properties make them very interesting materials for application as electrodes for many energy applications. These nanostructured materials present an increased surface area for hosting electrochemical reactions. Furthermore, active species can diffuse fast when NMFs are used. They also combine the abovementioned properties with characteristics of metals, such as good electrical and thermal conductivity and ductility/malleability. Nanoporous metals (NMFs) are synthesized using different approaches such as dealloying, sacrificial templating, dynamic hydrogen bubble templating, combustion synthesis, sol-gel, and nanosmelting. Nanoporous metals have been used for creating drugs for cancer, catalysis of reactions due to their high surface area, capturing hydrogen and carbon into their pores and surface, platforms for cell culture, and other numerous applications. In addition, NMFs could find potential applications in many fields, such as sensors, actuators, fuel cells, lithium-ion batteries, metal-air batteries, and supercapacitors. It is still a great challenge to develop convenient and tunable methods for the fabrication of nanoporous films with a high surface area. The use and development of green electrochemical synthesis mechanism in nanotechnology will be also discussed.