A water jet cutter is a tool capable of machining metal or other materials using a jet of water at high velocity and pressure, or a mixture of water and an abrasive substance. The process is essentially the same as water erosion found in nature but accelerated and concentrated by orders of magnitude. It is often used during fabrication or manufacture of parts for machinery and other devices. It has found applications in a diverse number of industries from mining to aerospace where it is used for operations such as cutting, shaping, carving, and reaming.

The Water Jet Cutting process is controlled using a stream of pressurized water passing through a tiny hole. It is one of the fastest, safest and cleanest methods of fabrication. Accuracy and productivity are key benefits of the technology, not to mention the reduced cost for low and high volume runs.

The most important benefit of waterjet cutting is its ability to cut material without interfering with the material's inherent structure as there is no "heat affected zone" or HAZ. This allows metals to be cut without harming or changing their intrinsic properties.