APPLIES TO: Business Central Online only. S2S for automation APIs requires 2020 release Wave 2 (version 17.0) or later. S2S for standard Business Central APIs, custom APIs, and web services requires Business Central 2021 release wave 1 version 18.3 or later
A few days ago, Microsoft published some information on the subject of communication and authentication between online services.
In such scenarios, Basic authentication and its credentials cannot be used because it is not an actual user initiating interaction with Business Central. Instead, it’s a different service or application, such.B as an automation flow, a background service or process, an external web portal, and more. Modern online services use Azure Active Directory applications and service-to-service (S2S) authentication to securely establish this communication through APIs. S2S offers a more secure alternative than Basic Auth/Web Service Access Key.
To set up S2S, consult the documentation:
Using Service-to-Service (S2S) Authentication with Business Central
Sample implementations MSAL using S2S
Visual Studio Rest Client sample connecting to Business Central