A computer-implemented method for coordinating documents between computer systems includes identifying, on a computing device, changes made by a user to a document having a model stored on the computing device, with corresponding models stored on a remote client and a server system; generating from the identified changes, one or more mutations that describe the changes and a one or more locations that correspond to positions in the model where the changes are to be provided; receiving one or more mutations from the server system and transforming the generated mutations using the received mutations; and updating the model stored on the computing device using the transformed mutations.