How to Check If User Has Valid Mailbox?

Question

I am calling the list users API call, but I would like to exclude any user that doesn't have a valid Office 365 mailbox. Is there a way to do this? Basically the same question as https://learn.microsoft.com/en-us/answers/questions/472337/find-if-a-user-has-a-mailbox-or-not-using-graph-ap

Answer 1

Hello WillBurner-4298,

Thanks for reaching out!

As per my research you can get details of a user with a valid mailbox having a default Exchange online plan by using the MS Graph API endpoint:
GET /users/{id|userPrincipalName}/mailboxSettings

Permissions required to run this API: MailboxSettings.ReadWrite

If the user has a mailbox, the API will return a JSON object that includes the mailbox settings for the user, including the mailboxGuid, archiveGuid, and outlook, among others. Please refer the link for more details.

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