How to access SharePoint Online APIs from App, not user auth

Question

I am looking to grant an application access to write to our SharePoint Online lists. We have Azure AD setup as an option. I don't want to prompt users for authentication/access, I want the app to get a token and then access SPO.

I got as far as creating the AAD App registration, and I can get the token from there, but I can't get into SharePoint. The App reg has Permissions to SPO

But my gut is that I need to allow this access in my site collection, and that's where everything goes dark. No idea where/how to do that. If I'm even on the right path.

UPDATE

I tried going down the Graph path, but to read/write list items is in Beta, and even that wasn't working, see other post https://stackoverflow.com/questions/44554169/access-sharepoint-sites-lists-via-microsoft-graph

Answer 1

To access your SharePoint online site from any APP using preferred technology Microsoft Graph is the best way to do that.

Microsoft Graph exposes multiple APIs from Office 365 and other Microsoft cloud services through a single endpoint: https://graph.microsoft.com.

You can read below article to understand and get started.

Overview of Microsoft Graph API

Get Started with Microsoft Graph API

Working with SharePoint sites in Graph API

Answer 2

To write item sharepoint list your app should have below permission

Permission type Permissions- (from least to most privileged) Delegated (work or school account) -Sites.Manage.All Application- Sites.ReadWrite.All

Post URl: POST https://graph.microsoft.com/v1.0/sites/{site-id}/lists

POST /sites/{site-id}/lists Content-Type: application/json

{   "name": "customer list",   "columns": [
    {
      "name": "name",
      "text": { }
    },
    {
      "name": "address",
      "text": { }
    }   ],   "list": {
    "template": "genericList"   } }