API development and integration should establish stable identifiers and field ownership, identity, scopes and interface contract and retry, exception and reconciliation evidence. Existing systems remain authoritative until owners, interfaces, data rights and acceptance rules are documented.
Start with one authoritative system handoff. Name the source record, accountable owner, exception route and acceptance evidence for warehouse and movement status; then test how supplier and port handoffs and release and dispatch evidence change the design before extending the scope.