A pizza oven that is fired solely by gas, either natural gas from the city’s main lines, or propane in a tank or canister. Some ovens only work with propane, while others work with both through a conversion kit. Typically “gas-fired” means the oven is fired only by gas, and you don’t have the choice of swapping burners between gas and wood, or using gas or wood but not both without swapping burners, or using both gas and wood at the same time. Ninja has an oven that is gas-fired that allows you to burn pellets for wood-flavor and not heat, which is innovative.