IEC 62656-8:2020 specifies a web service interface to exchange data parcel(s) conformant to IEC 62656-1, between a parcel server and a parcel client or between parcel servers. This interface comprises three basic services: a registration service, resolution service and subscription service.This document includes the following:– holistic use scenario;– detailed specification of the three basic services;– JSON and XML notation schemas for data parcel(s).The following items are outside the scope of this document:– user identification and authorization;– query language for a data parcel;– transportation protocol;– data and communication security techniques.