Hoppers, also known as loaders, hold paintballs for the marker to fire. There are many variations, but the primary types are gravity feed, agitating, and force feed.

One common problem to all hoppers is ball breaks. When a paintball leaks its contents into the hopper from either a break in the hopper or from a previous container, the leaked material (which is usually water based) causes the gelatin shells of the balls to deteriorate and sometimes stick together.

While agitating and force feed hoppers result in a higher possible rate of fire, they may fail due to dead batteries and contact with moisture, which keeps many woodsball and scenario players away from them.

Gravity feed is the simplest and cheapest form of hopper available. Gravity feed hoppers consist of a large container and a feed tube molded into the bottom. Paintballs roll down the sloped sides into the tube. These hoppers are limited to an intermittent 8 balls per second. Gravity feed hoppers are very cheap, since they are made of only a shell and a lid, but can become jammed easily as paintballs pile up above the tube. Occasionally, rocking the marker and hopper can keep the paintballs from jamming at the feed neck.

This problem is made worse when using a modern fully-electronic marker. Most economic and mechanical markers use a blowback system for recocking, or other methods where a large recriprocating mass is involved. This will shake the balls in the hopper slightly, facilitating gravity feed. A marker with both electronically controlled recocking and firing will often exhibit no shake whatsoever while operating. Because of this, small packs in the hopper are not broken up, and feeding problems are made worse.

Stick feeds are primarily used on pump and stock-class markers and are simple tubes that hold ten to twenty paintballs. Usually stick feeds are parallel to the barrel and the player must tip (or rock, leading to the term, rock'n'cock) the marker to load the next paintball. Some stick feeds are vertical, or at an incline to facilitate gravity feeding, but this contravenes accepted stock-class guidelines.

Agitating hoppers use propellers to agitate, or stir up, the paintballs. This prevents them from jamming at the feed neck and feeding more rapidly than equivalent gravity feeds. Older tournament-level hoppers are of the agitating type, since the higher rate of fire requires a more advanced and consistently-loading hopper.

Unlike the previous types of hoppers, there are two types of Agitating Hoppers: those with eyes and those without. These eyes are two electronic devices inside the neck (tube) of the hopper and are often inside electronic markers. Eyes are used to detect whether a ball is present or not. In a marker, the eyes will keep the gun from shooting until a ball is fully loaded into the chamber. In a Hopper the eyes detect when a ball is not present to cause it to turn. Agitating hoppers without eyes will run down batteries and may bend or dent paintballs which will in turn cause a short, less air efficient, skew shot. Agitating hoppers with eyes will only spin whenever there is not a ball, which causes less chance of damage and longer battery life.

One notable agitated hopper is the Tippmann Cyclone system. It is used on the Tippmann A5, X7, and can be installed on the 98 Custom. The Cyclone system uses excess gas from the blow back to force feed a ball into the gun. There are several benefits to this, it does not require batteries, and it only cycles when the gun fires. There are, of course, several downfalls to the Cyclone system as well. The Cyclone requires more CO2/HPA, therefore makes the gun less air efficient, and it adds many moving parts to the marker, decreasing the reliability.

Force-feed hoppers are superficially similar to agitated hoppers. They can use a propeller, be spring-loaded, or utilize a belt-fed system to force balls at an accelerated rate into a marker. The difference between the two styles is that the design of the feed mechanism does not rely on gravity to move paintballs into the feed neck. Instead of simply agitating, the device actually captures the paintball. These are the dominant form of hopper, as modern markers outshoot what gravity can supply. few markers use force-fed loaders shaped in imitation of firearms magazines such as the Real Action Paintball RAP-4. They are also appealing when a low profile is required, such as woodsball 'sniper' positions, as the force-feed nature allows the hopper to be mounted in non-standard locations. Some also include other features, which may include information about how many balls are remaining in the hopper, how many balls per second are being fired, and game timers.

The newest type of force feed hoppers communicate wirelessly with the marker's electronics via radio frequency. This allows the hopper to begin feeding paintballs before the pneumatic system of the marker has even began cycling the next shot. Not only does this system almost totally eliminate mis-feeds, but it can greatly increase the speed of the loader and increase battery life due to the loader only being in operation when the marker is preparing to fire, as opposed to the continuous operation of many other loaders. An example of the radio frequency activated hopper is the DXS/Draxxus Pulse. It should be noted, though, that Procaps (the maker of the Pulse) is being sued by NPS (maker of the Halo B, another force-fed hopper) for alleged intellectual property theft of the magnetic aspect of the RF Chip and the internals of the Halo hopper. DXS/Draxxus has halted production of the Pulse, and its future production is unclear.

It should be noted, however, that in order to use this feature, you must have a chip soldered to the electronics board in your marker. Fortunately, many new marker manufacturers and aftermarket electronics makers have announced that their markers/boards will support this new technology.