Declarative synchronization of shared data

Methods and apparatus, including computer systems and program products, related to declarative synchronization of shared data. One method includes receiving one or more changes to data maintained by one of multiple computer programs having respective local copies of the data, identifying an event characterizing synchronization of the data maintained by the computer program with the other computer programs (e.g., with a local copy managed by the other computer program), and initiating synchronization of the changes with one of the other programs having respective local copies (e.g., with the local copy managed by the other program) in response to the event occurring. The event can be characterized by an annotation. Identifying an event can include reading a property of a data object (e.g., in a data object graph of shared data).