We have a developer account that manages many other client accounts (for creating provisioning profiles, releases, etc.). So far we use cookie authentication via fastlane to upload the releases, but we want to move to the API key authentication (https://docs.fastlane.tools/app-store-connect-api).
The question is:
Do we have to create only one API key via Apple Developer Console for our account, or do we have to create a new API key for each individual client account?