Editing an unhosted third party application

A system for enabling a user to communicate with an application server to edit a file and save file data in a storage repository controlled by the user, distinct from data storage managed by the application server, comprising:

• one or more processors;
• and
• memory storing instructions that, when executed by the one or more processors, cause the system to perform:
• receiving, from a third-party-controlled remote server that is client-side relative to a server-side application server that hosts a document editing application, a request to process a modification to a file maintained in a file storage repository, the file storage repository being distinct from data storage managed by the server-side application server, the file having a first file format;
• in response to the request, executing, at the server-side application server, the document editing application to process modification of the file based on the request;
• sending a response to the request from the server-side application server to the third-party-controlled remote server, the response including file data for presenting the file by a third party application hosted by the third-party-controlled remote server and enabling display of at least a portion of the file using the file data at a user interface generated at a client device;
• converting, at the server-side application server, the file into the file having a second file format in accordance with the request;
• sending, by the server-side application server to the third-party-controlled remote server, the file having the second file format;
• saving, by the third-party-controlled remote server, the file having the second file format in the file storage repository in the client-side network;
• deleting, by the server-side application server, the file data.