We have an app that creates MS Graph Subscriptions where a user wishes to 'track' an outlook email conversation. The subscription uses the conversation id of the email to send notifications when an email within the conversation is sent or received. Once we receive a notification from MS Graph, we then use the message id to get details about the email so we can store it in our CRM.
I am trying to find information on what the limitations/throttling are in regards to this. I have read the info here and here but neither are very specific. I also raised a GitHub issue with the MS Graphs docs team here but they have not responded.
I really want to know:
Is there a limit for Outlook based Graph subscriptions per user?
Yes, there is limit. Each user or group can request 10,000 API calls in a 10 minute period. It could be same for user and group as
well. You could have a look at this official document.
Is there a limit to the number of messages that we can retrieve per user?
Normally 500 messages per user can retrieve but it is customizable. You can customize it up to 1000 for each user.
For more details, you could have a look at the official document here.