Abstract: The present invention relates to a computer-implemented method and system for device optimized rendering and storage of files to mobile devices. Only the individual parts of a file being accessed by the user are transmitted to the mobile device requiring significantly less bandwidth and time in contrast to downloading a complete file. The file is deconstructed into parts and a data structure is created that associates the individual parts of the file. At least one part of the file is transmitted to the requesting client in a “view only” format. A separate, “editable” format of the same part of the file is transmitted to the client in response to a request to edit the file. When the “editable” part of the file is saved, the updated file part is transmitted to the server and is merged with the master file while retaining the original formatting and the process begins again.