Providing synchronization to a local system. Embodiments may include downloading a batch of changes in a heterogeneous batch. The batch of changes is correlated to an anchor affiliated with a synchronization service. The anchor is a reference point indicating time or relative order. The batch of changes and the anchor are serialized to a non-volatile storage medium as a heterogeneous set. After serializing the batch of changes to a non-volatile storage medium as a heterogeneous set, entities in the batch of changes are parsed out into entities in in-memory representations. Similarly, embodiments may receive user input modifying a plurality of data entities, store on a non-volatile storage medium a serialized heterogeneous representation of the modified data entities, and upload the serialized heterogeneous representation to a synchronization service.