Known micromixers for fuel injection (e.g., in a gas turbine engine) experience early burning or have limited operability. Accordingly, a micromixer is disclosed that utilizes an air nozzle, in combination with one or more fuel jets, to produce short flames that minimize the emission of nitrogen oxides, while providing additional benefits, such as mechanical robustness, aerodynamic efficiency, resistance to flame damage, suitability for additive manufacturing, wider operating ranges, operation with a variety of gaseous fuels, and/or amenability to control using conventional mechanisms.