Web Application Open Platform Interface (WOPI) is a protocol that enables a client to access and change files stored on a server. The protocol was first released as v0.1 by Microsoft in January 2012, [1] but as of February 2025, the current specification is v14.5. The protocol has been adopted by applications outside of Microsoft, such as by Collabora Online, Google, ownCloud and Nextcloud. [2] [3] [4] [5]