Airsoft refers to a class of replica air powered guns that originated from Japan (although the origins go back to the US in the 70s). The power levels are way below those of traditional airguns, but the guns are 1:1 scale copies of original pistols, rather than original designs.

While most electric guns also use springs for this they are not considered to be in the same category as the single-shot spring-powered guns. Low-end spring guns tend to be much cheaper than their electric-powered equivalents due to their simplicity and cost of components (spring assembly vs. spring assembly, electric motor, battery, and battery charger) and thus are widely available. These guns are less suited for competition because they are at a disadvantage against automatic guns in close combat and don't provide enough accuracy and power for long-range uses. Higher-end spring-powered airsoft rifles can be quite expensive; these guns are typically suited for "sniper" applications in airsoft matches and can provide competitive muzzle velocities.

Gas power tends to be used in airsoft pistols where size constraints make electric-powered mechanisms impractical. Other instances where gas is favored are where adjustable velocities are required or where a blow-back feature is desired. A blow-back feature is a mechanism which cycles a slide or bolt to better simulate a real firearm's operation. Because of the mechanical complexities involved with distributing and regulating gas these guns have largely given way to electric guns for less specialized applications.

These guns were originally developed in Japan, and the Japanese model giant Tokyo Marui dominates the market today with many quality models. In a Marui AEG, the motor drives a series of 3 gears mounted inside a gearbox. The gears then compress a piston assembly against a spring. Once the piston is released, the spring drives it forward through the cylinder to push a pellet into the chamber, through the barrel, and forward from the muzzle. Many manufacturers have now more or less replicated this basic model, adding reinforced parts or minor improvements.