The following contents covers a basic overview of the EC API Technology.
Objective
The following contents covers a basic overview of the EC API Technology.
OData offers partners and customers a consistent API experience for the Intelligent Enterprise.


Import/Export: CSV File (automation via FTP possible)
SOAP APIs
OData APIs
Compound Employee

Back to the Entity Relation Diagram, it shows the Compound Employee API includes a set of entities which are surrounded by orange line. Compound Employee API is a kind of EC SOAP API technology and it focused on replication employee master data from Employee Central.
Request:

Response:

If we query Compound Employee, the query clause is no longer fields but the entities name (person, personal_information) which compared with SAP SuccessFactors direct API.
EC OData APIs using navigations incl. MDF

OData APIs supports navigation for associated entities, it automatically creates navigations from the source entity to the target entities, based on the relationship defined. Navigations in an entity represent associations between entities. Each entity can have the following properties.
Look at this API request and response, we can easily extend existing Employee Central (EC) entities (personalInfoNav) by using expand functionality and build EC customer extensions for partners and customers. MDF allows you to customize customer objects and related application logic as needed to meet your client's needs.
Request:
https://salesdemo4.successfactors.com:443/odata/v2/PerPerson?$format=json &$select=personIdExternal,dateOfBirth, personalInfoNav/startDate, personalInfoNav/firstName, personalInfoNav/lastName, personalInfoNav/customString1&$expand=personalInfoNav &$filter=personIdExternal%20eq%20'greinhard3‘
Response:

When to use imports/export…
When to use OData and when SOAP…
When to use SOAP Compound API…
OData:
SOAP API:
More Information:
SOAP Interface
File based Imports