An electrical receptacle connector includes an insulated housing in a metallic shell. First and second receptacle terminals are on the insulated housing. The receptacle terminals include first and second high-speed signal terminals. The metallic shell includes a receptacle cavity for receiving the insulated housing, an insertion opening being in communication with the receptacle cavity, pins at two sides of the metallic shell and outwardly extending, and an external protruding structure on a bottom surface for connecting to a circuit board. The external protruding structure forms an enclosed structure. Therefore, the seamless configuration improves the reduction to electromagnetic interference.