The methane-fueled engine used by SpaceX’s Starship vehicle is called Raptor.
Raptor is a full-flow staged-combustion engine designed to burn liquid methane with liquid oxygen. Starship uses Raptor engines on both its Super Heavy booster and its upper-stage Starship spacecraft. The choice of methane supports high performance and is compatible with the idea of producing propellant from Martian resources in a future settlement architecture.
Raptor is different from Merlin, the kerosene-fueled engine used by Falcon 9 and Falcon Heavy. Blue Origin’s BE-4 is also methane-fueled, but it is a separate engine developed for Vulcan and New Glenn-related launch systems. Earlier Starship prototypes used Raptor variants before SpaceX introduced newer versions with changing engine arrangements.