Apple assigns every Apple Developer Program account a Team ID: a stable 10-character alphanumeric string like ABCDE12345. It is the prefix Apple uses to scope every certificate, provisioning profile, App ID, push notification topic, App Group, and iCloud container to your team.
Where you see it
- App Store Connect: under Membership > Team ID.
- Apple Developer portal: in the upper-right account dropdown.
- Inside every provisioning profile (
TeamIdentifier) and certificate (OUfield). - In Xcode build settings as
DEVELOPMENT_TEAM. - In
codesign -dvv MyApp.appoutput as the second component of the Authority chain (Apple Distribution: Acme Corp (ABCDE12345)).
When it matters more than usual
- Universal links and shared App Groups require the same Team ID across every related app and extension.
- Switching teams (acquisitions, contractor handoff) means re-registering every App ID, regenerating every profile, and submitting a Transfer of an App through App Store Connect.
- Shared keychain access between two apps requires they live under the same Team ID.