Abstract: In a directory service, a sync request requesting changes to a dataset is received from a sync client, the sync request comprising a token, and sync requests containing tokens are sent to first and second directory servers. Changes are returned by the directory servers with tokens, and the changes are returned to the sync client with a unified token. In embodiments, the changes returned to the sync client are new to the sync client. Also disclosed is a method where a request for new changes to a dataset is received from a sync client, the request including a token, and a response that contains a token and changes that are new to the sync client is returned.