Developers working for customers and partners of SAP build extension applications that consume application programming interfaces, or APIs (hereinafter we talk only about REST APIs), from various SAP®application providers, such as SAP S/4HANA®, and from Concur®, SAP SuccessFactors®, and SAP Ariba®solutions, to name a few. They expect that the APIs that SAP provides are of high quality and conceptually consistent across all software-as-a-service SAP products, regardless of the SAP development organization that provides them. To put it simply, consumers expect APIs from SAP to be harmonized.
SAP acknowledges this consumer expectation and recognizes the need for harmonizing APIs throughout SAP software. In response to this need, SAP defined API harmonization guidelines for its developers to help them carry out this challenging task in the future. However, since customers and partners of SAP also build their own APIs that they might want to offer to other consumers in the ecosystem, we decided to make these guidelines available to them in this reference guide.
The intention of this paper is to cover as many aspects of APIs as possible. Nevertheless, we could not always formulate standard procedures. For example, the question of when to select OData or plain REST can be answered only with “it depends.” In addition, business case–specific requirements and technical conditions may also lead to constraints or even exceptions to the guidelines contained in this document.
Ideally, API implementation teams at customer and partner sites can directly apply the guidelines provided in this document. If necessary, of course, they also have sufficient flexibility to adapt them to the special requirements of their respective business scenarios. Nevertheless, if possible, these specific adaptations should not contradict the core statements of the guidelines provided here.
SAP’s Guidelines for Future REST API Harmonization