Hi @Aleksi Pulkkanen ,
You'll undertake the four steps needed to convert a single tenant app into an Azure AD multi-tenant app:
- Update your application registration to be multi-tenant
- Update your code to send requests to the /common endpoint
- Update your code to handle multiple issuer values
- Understand user and admin consent and make appropriate code changes
Reference: Making your application multi-tenant.
You can also refer to the sample: Build a multi-tenant SaaS web application that calls Microsoft Graph using Azure AD and OpenID Connect.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.