An espresso machine is a cooking appliance that brews coffee by forcing pressurized water near boiling point through a "puck" of ground coffee and a filter in order to produce a thick, concentrated coffee called espresso. Multiple machine designs have been created to produce espresso. Several machines share some common elements, such as a grouphead and a portafilter. An espresso machine may also have a steam wand which is used to steam and froth liquids (such as milk) for coffee drinks such as cappuccino and caffè latte.

Espresso machines may be steam-driven, piston-driven, pump-driven or air-pump-driven. Machines may also be manual or automatic.

Angelo Moriondo, from Turin, patented a steam-driven "instantaneous" coffee beverage making device in 1884 (No. 33/256). The device is "almost certainly the first Italian bar machine that controlled the supply of steam and water separately through the coffee" and Moriondo is "certainly one of the earliest discoverers of the expresso [sic] machine, if not the earliest". He was granted patent no. 33/256 dated 16 May 1884 (according to the "Bollettino delle privative industriali del Regno d'Italia", 2nd Series, Volume 15, Year 1884, pp. 635 – 655). Unlike true espresso machines, it brewed in bulk, not as individual servings.

Seventeen years later, in 1901, Luigi Bezzera, from Milan, devised and patented several improvements to the espresso machine, the first of which was applied for on 19 December 1901. Titled "Innovations in the machinery to prepare and immediately serve coffee beverage"; Patent No. 153/94, 61707, was granted on 5 June 1902. In 1903, the patent was bought by Desiderio Pavoni, who founded the La Pavoni company and began to produce the machine industrially, manufacturing one machine daily in a small workshop in Via Parini, Milan.

Numerous machine designs have been created to produce espresso. Several machines share some common elements.

Varying the fineness of the grind, the amount of pressure used to tamp the grinds, or the pressure itself can be used to vary the taste of the espresso. Some baristas pull espresso shots directly into a pre-heated demitasse cup or shot glass, to maintain a higher temperature of the espresso.

The piston-driven, or lever-driven, machine was developed in Italy in 1945 by Achille Gaggia, founder of espresso machine manufacturer Gaggia. The design generically uses a lever, pumped by the operator, to pressurize hot water and send it through the coffee grounds. The act of producing a shot of espresso is colloquially termed pulling a shot, because these lever-driven espresso machines required pulling a long handle to produce a shot. Lever-driven espresso machines are sometimes called manual espresso machines because of this.

There are two types of lever machines; manual piston and spring piston design. With the manual piston, the operator directly pushes the water through the grounds. In the spring piston design, the operator works to tension a spring, which then delivers the pressure for the espresso (usually 8 to 10 bar; 116 to 145 psi).