The Cosync Storage module provides a number of services for a collaborative application that is built on top of MongoDB Realm. Specifically, the Cosync Storage module implements a bridge between MongoDB Realm and the Amazon S3 Storage service. To implement this functionality, Cosync defines a number of data models that define collections of objects that reside within the MongoDB Atlas Cluster that supports the corresponding MongoDB Realm application.

These data models define objects that are synchronized by MongoDB Realm and therefore exists within MongoDB Realm partitions. Each data model contains a _partition property that contains the partition key value for the object. For more discussion about partitions, please consult the MongoDB Realm documentation at partition strategy. The default behavior of the Cosync Storage module is to assume a partition key property called _partition.

All of the Cosync Data Models are open source, and are released under the Apache 2.0 license.

Cosync defines data models for the three language binding it supports:

• Swift
• Kotlin
• React-Native

The specifics of the Cosync Data Models are discussed here.