Process, and apparatus, for the production of hydrogen and carbon monoxide in a reactor, preferably one containing a bed of a particulate solids catalyst, or catalyst and solids diluent, by contacting and reacting within the reaction zone a low molecular weight hydrocarbon feed, steam and oxygen, or a low molecular weight hydrocarbon feed and oxygen, at high temperature. An oxygen stream preheated to high temperature is fed via a nozzle inlet, or inlets, into the reactor, while the hydrocarbon and steam, or hydrocarbon, is fed via a different nozzle inlet, or inlets, into the reactor. Preferred oxygen nozzle designs are constituted of nickel-chromium-iron alloys, especially Inconel 600, and Inconel alloys of the 600 series generally. The oxygen nozzle is comprised of a tubular body with inlet, and outlets of special design, which renders the nozzle especially useful in the intensely hot oxygen environment.