Answer
Network calls can break off even though the target has already processed the case. Webhooks can also be sent again. That is why every important case needs a stable external identifier and idempotent processing: the same business order must not be created a second time unnoticed when a call is repeated.
In addition, states such as “received”, “checked”, “accepted”, “rejected” and “to be checked again” are distinguished. Retries are controlled and have a traceable result. In asynchronous processes, a queue can prevent a target that is briefly unavailable from immediately causing data loss. No technology guarantees that an error will never occur. The goal is that an error is detected, assigned to a specific case and can be processed again without risky manual work.
As of 3 September 2026
Further reading
Related topic: Back ends and interfaces