EDI 850/855/856 with SAP / Oracle / NetSuite ERP, what’s the integration pattern?

Orders flow from Magento (customer-facing order-of-record) to your back-office ERP (financial system-of-truth). The pattern:

• SAP S/4HANA, integration via IDoc (the SAP-native EDI-equivalent) or REST API through SAP Integration Suite (formerly SAP CPI). Pattern: Magento order placement → webhook → middleware → SAP Sales Order (VA01) → invoice (VF01) → GL posting. The SAP Commerce / Hybris connector exists but is heavy ($$); custom Boomi / MuleSoft middleware is typically lighter for mid-market resellers.
• Oracle NetSuite, SuiteTalk REST API or SuiteScript. Native Celigo connector for Magento exists ($600, $2,000/mo) and handles Customer, Sales Order, Item Fulfillment, Invoice, Cash Sale, Customer Payment. Recommended for resellers under $50M ARR, way less custom code than building it.
• Oracle E-Business Suite (EBS) R12, legacy but still common at large IT distributors. SOAP / REST via Oracle Integration Cloud (OIC). More custom work; budget $40k, $120k for the initial integration.
• Microsoft Dynamics 365 Business Central / F&O, common at sub-$50M resellers. Native connectors exist via Power Automate / Logic Apps.

Returns + RMA flow back the same path: customer initiates RMA in Magento → webhook to ERP → RMA approved in ERP → credit-memo issued → Magento order status updated.

Critical: idempotency keys on every webhook. Network blip retries the same payload twice; without idempotency you double-post the same sales order to SAP. I’ve seen six-figure mismatches caused by this.