check if you can retrieve using odata.
please refer Hands-On – Testing Integration with SuccessFactors OData API
try to construct the url if you can get the data.
https://<data center>.successfactors.com/odata/v2/EntitySetName
joins will be possible i guess. that is called "“expanding”. see the below statement from api guide.
Of course, there are many more things to consider, including filtering, paging, sorting, joining to other entities (known as “expanding” in OData), etc. Examples of these details are described below.