An in-ear receiver can be used in a headset and/or hearing aid and includes a housing in which at least one ear canal section is configured to be inserted into an ear canal of a wearer when the in-ear receiver is used as intended. The housing defines at least one outer contour that is configured with at least in one section adapted to the ear canal of the wearer. The in-ear receiver includes a sound transducer arranged in the housing, and at least one resonant cavity, which is formed in the housing and is divided by the sound transducer into a front volume and a rear volume. The sound transducer is a MEMS sound transducer, and the front volume and/or the rear volume have/has an inner contour adapted to the ear canal.