Electroplating is the general name for processes that coat metal on a solid substrate by reduction of cations of that metal by means of a direct electric current. The part to be coated acts as the cathode (negative electrode) of the electrolytic cell; the electrolyte is the solution of the metal salt to be coated; and the anode (positive electrode) is usually either a nugget of that metal or some inert conductive material. Current is supplied by an external power supply.

It is widely used in the electroplating industry and decorative arts to improve the surface properties of objects such as wear and corrosion resistance, lubricity, reflectivity, electrical conductivity or appearance. It can also be used to build thickness on small sized or worn parts, or to produce metal plates with complex shapes, a process called electroforming. It is also used to purify metals such as copper.