A document collaboration system allows applications to collaborate on a binary data file even if the binary data file is not in a collaborative document format. In response to a request from an application to access a binary data file, the document collaboration system gives the application access to a document model corresponding to the binary data file and the application. If the document model does not already exist, it may be created by generating an empty document model, transmitting the binary data file to the application, and allowing the application to fill in the empty document model based on the binary data file. The document model may be provided to and modified by its related application through an application programming interface (API), and changes to the document model may be applied to the binary data file.