The invention provides federated functionality within a data processing system by means of a set of specialized runtimes. Each of the plurality of specialized runtimes provides requested federation services for selected ones of the requestors according to configuration data of respective federation relationships of the requestors with the identity provider. The configuration data is dynamically retrieved during initialization of the runtimes which allows the respective runtime to be specialized for a given federation relationship. Requests are routed to the appropriate specialized runtime using the first requestor identity and the given federation relationship. The data which describes each federation relationship between the identity provider and each of the plurality of requesters is configured prior to initialization of the runtimes. Configuration data is structured into global specified data, federation relationship data and requestor specific data to minimize data change, making the addition or deletion of requesters very scalable.