This series of documents defines the use cases and their associated APIs for the SOVD and fall within the scope already defined by ISO 20077-1 "ExVe”. The methodology adopted for the implementation of an SOVD API is intended to follow the definitions in ISO 20077 (all parts) regarding “Extended Vehicle (ExVe)” (definitions, basic principles, rules, uses cases, API, etc...). It specifies the way to diagnose the vehicle via High Performance Computer (HPC) and Electronic Control Unit (ECU). The SOVD API provides, in the ExVe perimeter a unified access to ECUs and HPCs. This access can be performed remotely (e.g., backend or cloud), nearby in the repair shop (e.g., repair shop test equipment), or in the vehicle (e.g., on-board application). The SOVD API leverages existing technologies: • The API follows the Representational State Transfer (REST) principles and uses Javascript Object Notation (JSON) for encoding the transmitted data. • SOVD uses Hypertext Transfer Protocol (HTTP) 1.1 but for achieving the best communication performance HTTP/2 is recommended. No HTTP/2 specific features are used. • The SOVD API utilizes the OpenAPI specification to define the API as well as the diagnostic capabilities of the vehicle. • The authentication and authorization of clients builds upon OpenID Connect and Open Authentication (OAuth) 2.0, but a vehicle manufacturer may use other authentication mechanism like certificates if required. The SOVD API provides the following functions in the perimeter of the Extended Vehicle: • Clients can access the faults, including reading the fault entries, reading environment data, and deleting fault entries. • Measurements and identifications from all entities in the vehicle can be read. In addition, identifications may be written as well. • SOVD supports the execution of routines, I/O controls, and software functions. Their execution can only be performed in certain modes or states. Thus, an SOVD client can set the component into a specific mode. • The configuration of a vehicle (e.g., equipment, country, customer demand, variant coding etc.) can be read and written using the SOVD API. • SOVD provides an interface to initiate and monitor a software update for a vehicle • SOVD provides access to Extended Vehicle logging information With these features SOVD covers the entire chain of the vehicle life cycle: engineering (development), manufacturing (production), storage park, sales, vehicle operation (usage), maintenance and repair, technical inspection, recycling (re-use). This document provides general information, specifies common definitions applicable for SOVD and defines overall rules and basic principles.