A key programmer is a device or software used in the automotive industry to program or reprogram electronic keys (also known as transponder keys) for vehicles. These keys contain a small microchip that communicates with the vehicle’s immobilizer system to allow the engine to start. Key programmers are essential for various purposes, such as creating duplicate keys, replacing lost keys, adding new keys to a vehicle’s system, and even reprogramming keys after a vehicle’s immobilizer system has been changed or updated. They are commonly used by locksmiths, auto dealerships, and repair shops to provide key-related services.