Office Web Apps are using ASP.NET SignalR to power real-time co-authoring

Xinyang Qiu

Office Web Apps are now using SignalR as the backend to synchronize changes when two or more people are editing files on SkyDrive or on SharePoint Online.  SignalR enables real time communication among different browsers and native mobile apps to communicate with each other through the backend server.  It is flexible, scalable and offers great performance, demonstrated by its usage in SkyDrive Office Web Apps.

To verify its usage in Office web apps, let’s go to SkyDrive and create a word document.


Log on another computer and edit the same SkyDrive document from any browser. SignalR works cross browser and will auto-select the appropriate real-time transport.


F12 on IE11 to bring up the Developer Tools, go to debugger and search for “SignalR” in the scripts to verify its usage.


Go to to learn more about Office Web Apps real-time co-authoring.

Go to to learn more about SignalR!


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