Query Regarding Setting Shared Mailbox Permissions for Bulk Users Using Microsoft Graph API

Question

Dear Microsoft Support Team,

I recently initiated a service request regarding an issue with managing shared mailbox permissions using a PowerShell script (Reporting Managing Shared Mailbox Permissions Issue with PowerShell Script. - TrackingID#2308300030001978). As advised by your team, I am now reaching out to the Microsoft Graph API team for assistance with an alternative approach.

My current objective is to set shared mailbox permissions for multiple users in a bulk operation using Microsoft Graph API calls. However, I am encountering challenges in achieving this task effectively.

Specifically, I am looking for guidance and assistance on:

1. The correct endpoint and method within Microsoft Graph API to use when setting shared mailbox permissions for multiple users.
2. Any specific parameters, headers, or request payloads that need to be included in the API request for bulk shared mailbox permission updates.
3. Best practices or considerations when working with shared mailbox permissions via Microsoft Graph API to ensure a smooth and efficient process.

I am committed to resolving this issue and greatly appreciate your expertise and support in helping me achieve my goal. Any documentation, code samples, or step-by-step instructions you can provide would be immensely valuable.

Thank you for your time and assistance in advance. I look forward to your guidance on utilizing Microsoft Graph API for setting shared mailbox permissions for bulk users.

Best Regards,

Prakash Chalgeri

Answer 1

There is no Graph API endpoint for managing mailbox permissions, or any other Exchange admin action for that matter. Not sure who you've spoken with, but they might want to refresh their knowledge on the Graph...

The only supported method for managing mailbox permissions in bulk is via Exchange Online PowerShell. There is an underlying API that you can call if needed, but that approach is NOT supported in any way by Microsoft, there is no documentation published on it, no throttling guidance, nothing. If that's not a issue for you, here's a sample article which discusses said API: https://www.michev.info/blog/post/2869/abusing-the-rest-api-endpoints-behind-the-new-exo-cmdlets