The EF 128 was a tailless swept-wing design and was to have been powered by a Heinkel HeS 011 turbojet and armed with four MK 108 cannons, reaching a speed of 1000 km/h at an altitude of 7000 m. A development contract was received in March 1945 but no progress could be made before the war ended.

The new aircraft was intended to have superior performance in order to deal with high altitude threats such as the B-29 Superfortress.

[1][2] By January design refinements included boundary layer suction, to help alleviate fears of transonic stagnation around the unusually positioned engine intakes.

Competing designs put forward at this time by other German aircraft makers were the Messerschmitt P.1110, Heinkel P.1078, Focke-Wulf Ta 183 and Blohm & Voss P 212.

[5][6] In March 1945 it was decided that the EF 128 and the more conventional Focke-Wulf Ta 183 should go into production as urgent interim solutions to the single-engine jet fighter requirement.