How to find the list of shared mailboxes using Graph API call?

Hi Kesava Chenna,

Thank you for reaching out to Microsoft!

Currently, there is no Microsoft Graph API available to which directly list all the shared mailboxes. You can upvote this features request idea Get a list of shared mailboxes and based on number of votes received Microsoft Engineering will consider for implementation.

Eventually, you can use the GET /users/{id|userPrincipalName}/mailboxSettings endpoint, which in its response has the "userPurpose" value to determine if the account is a shared mailbox or user mailbox. This method is helpful if you already have the UPN.

Alternatively, you can use Graph PowerShell or Exchange PowerShell to find shared mailboxes:

1. Get-MgUser | Select-Object UserPrincipalName, @{Name='MailboxType'; Expression={(Get-MgUserMailboxSetting -UserId $.UserPrincipalName).UserPurpose}} | Where-Object {$.MailboxType -eq 'shared'}
2. Get-Mailbox -RecipientTypeDetails SharedMailbox -ResultSize:Unlimited

For fetching group mailboxes, you can use the following endpoint: List Groups

GET https://graph.microsoft.com/v1.0/groups

Hope this helps.

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