The integration problem
Most operations run three separate systems: a TMS for movement, a WMS for inventory, and a customs platform for declarations. UK transit customs only works when those three share a common reference set.
Shared references that make the join
A shipment identifier, an EORI, a commodity code and an origin flag are the minimum shared fields. Add the export MRN, transit MRN and GMR once they exist, and the join becomes deterministic across systems. A field-level view is in this UK-EU freight compliance walkthrough.
Event triggers that keep systems in sync
Customs events — declaration accepted, transit MRN issued, GMR committed, arrival notification received — should trigger status changes in the TMS and stock releases in the WMS. Missing event wiring produces the classic "phantom pending" shipments that survive long after the truck has cleared.
FAQ
Can these integrations be built without APIs?
File-based integration works but adds latency. Event-driven APIs are strongly preferred for GVMS gate order.
Which system should own the primary shipment ID?
Whichever system creates the shipment first — usually the TMS. Every downstream system references it.
Ship customs as an event stream. Watch a demo with iCustoms.
