Thonem integration boundaries are easier to evolve when each adapter has explicit inputs, outputs, idempotency, error and reconciliation semantics.
Internal checkout creates a provider request through a narrow adapter. Provider state is translated back into internal payment/order state.
inputamount, currency, order/customer referencereturnprovider reference + actionable stateeventverified callback/webhookreconcilequery provider truth after uncertaintyShipment creation, labels, tracking and cancellation remain provider-specific while commerce workflows use normalized internal concepts.
inputshipment, address, package, service levelreturnshipment reference + label/tracking dataeventtracking/status updatefallbackmanual/retry path when automation failsSynchronization defines source-of-truth ownership per field or event instead of assuming bidirectional sync is always correct.
ownershipsystem of record by domainmappingidentifiers and normalized valuesretrybounded queue/replay semanticsaudittraceable sync resultThe machine-readable contract file documents categories and required implementation decisions. It contains no credentials, live endpoints or private provider configuration.