The Web Application Open Platform Interface Protocol (WOPI) defines a set of operations that enables a client to access and change files stored by a server. WOPI is a REST-based protocol. It defines a set of REST endpoints as well as operations that can be executed by issuing HTTP requests to those endpoints.

The WOPI protocol is used by Office applications, such as Office Online, to view and edit files that are stored in a cloud service. Thus, Office Online is a WOPI client, while the cloud service that stores the files is a WOPI server, often referred to as a host.

This documentation is a reference for all of the defined WOPI operations. However, not all operations must be implemented. WOPI is modular and a WOPI server need only implement the operations required by the WOPI client(s) the server intends to integrate with. To learn more about the specific requirements for integrating with Office Online or Office for iOS, see the sections below: