A receptacle connector assembly includes an outer housing and a terminal module. The terminals module includes an insulator having a base and a mating tongue extending from the base and equipped with a plurality of contacts. The contacts include front contacting sections exposed upon the mating tongue and tail sections extending out of the base. The outer housing is of an insulative molding part or a metallic die cast, the terminal module is assembled in the outer housing, and thus a mating cavity is directly defined between the mating tongue and the outer housing.