First define the source of truth
Each data type needs one clear authority: which system owns the product code, which owns pricing, which owns available stock and where customers are created. Without this decision, two systems may update the same field and create constant discrepancies.
Orders are only one part
A complete integration can cover products, prices, stock, customers, orders, payment methods, carriers, invoicing and statuses. Not every business needs every flow, but those selected need a clear direction and rule set.
What happens when something fails
An integration should never assume an API will always respond correctly. Logs, safe retries, clear error messages and visibility into failed records are essential. Failure should be visible and manageable, not discovered when a customer calls.
The value is reduced manual work
When the e-commerce platform and ERP have clearly defined responsibilities, duplicate entry, stock discrepancies and order-processing errors are reduced. That is the real return on integration: less repetitive work and more reliable operations.