Comparing the Office 365 Calendar connection options

Connecting OnceHub to your Office 365 Calendar ensures a real-time integration between your Office 365 Calendar appointments and your busy time in ScheduleOnce and InviteOnce.

You can connect to your Office 365 Calendar using an encrypted Exchange Web Services (EWS) connection or an encrypted OAuth 2.0 connection

In this article, you'll learn about the differences between the Office 365 Calendar connection options. 

Connection differences


Office 365 Calendar via OAuth 2.0
Office 365 Calendar via EWS
Connection methodConnection with the Office 365 API using a token generated by Microsoft.
Your sign-in credentials are never revealed during the connection process and are never stored by OnceHub.

Connection using your Outlook email address and either your Office 365 password OR an app password.
Learn more about how your credentials are stored and protected by OnceHub
Permissions requiredUses the minimum permissions required by Microsoft. Requires full access to your Office 365 account.
Two-way syncNot currently available
When enabled, calendar event changes in your connected calendar are automatically updated in your OnceHub Account. Learn more about two-way sync 
Corporate connectionNot currently available.
Corporate connection is available. Learn more about Office 365 corporate connection mode
Busy time cachingNot available.
When connected via EWS, OnceHub securely caches the start and end times of your calendar busy time.
Learn more about busy time caching
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