Microsoft Graph API – Retrieving Users' Working Hours via Service Principal

The endpoint in question does not support application permissions, so if your solution must use the work plan methods, we can only give you the bad news.

If you are open to using alternative methods, few things come to mind. First, you can fetch the user's free/busy (availability) info, which is possible via application permissions as well: https://learn.microsoft.com/en-us/graph/api/calendar-getschedule?view=graph-rest-beta&tabs=http

Another option is to fetch the user's working hours from the associated Exchange Online mailbox, either via the Graph's mailboxSettings resource or via PowerShell and the Get-MailboxCalendarConfiguration cmdlet: https://learn.microsoft.com/en-us/powershell/module/exchangepowershell/get-mailboxcalendarconfiguration?view=exchange-ps

All the above methods support application permissions, and in the case of Get-MailboxCalendarConfiguration, you can also query the underlying endpoints directly, bypassing the PowerShell layer if needed.

Hi Nataliia,

Yes, it can be confirmed your understanding is correct.

The Microsoft Graph endpoint: GET /users/{id | userPrincipalName}/settings/workHoursAndLocations does not support Application permissions. Microsoft Graph documentation stated only delegated permissions are supported and Application permissions are explicitly listed as "Not supported" for this API. Get workHoursAndLocationsSetting - Microsoft Graph beta

Therefore, even if your Service Principal is granted: it would still not be able to call the 'workHoursAndLocations' endpoint using an application-only token. The limitation is on the API itself rather than the permission assignment.

As an alternative, if your requirement is limited to retrieving users' standard working days, working hours, and time zone before creating Outlook events, you can use: This endpoint supports the MailboxSettings.Read Application permission and can be accessed using a Service Principal.
You may refer to the following Microsoft resources: Get user mailbox settings - Microsoft Graph v1.0 | Microsoft Learn

Hope this information would be helpful.

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Are there any alternatives, which we can use?