You can share a Sharepoint site without adding them to the member groups via the front-end (screenshot included). However I was wondering if there was a way to do this via the Microsoft Graph API?
I have scoured the docs, both v1 and beta and haven't found anything - so any help would be greatly welcomed.
According to the Microsoft Graph user voice, this feature is currently unavailable in the Graph API and is currently a suggested feature - will update this answer if/when it is implemented
Uservoice Sharepoint permission suggestion