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In brief
- GDI ERP remains the operational system for inventory management and order processes, while Shopify owns storefront, checkout and commerce experience.
- Middleware decouples both platforms, translates their data models and makes transfer failures controllable.
- Before development starts, data ownership, direction, frequency and the error path must be defined for every object.
- At PHARMOS NATUR, GDI ERP was integrated through middleware as part of the move from Shopware 6 to Shopify Plus.
What does the GDI-Shopify integration do?
The integration connects the Shopify sales channel to the operational processes in GDI ERP. Shopify is optimized for product presentation, customer journeys and checkout. The ERP coordinates inventory management, orders and downstream operations. Both systems need the same business events but model them differently.
GDI describes its Vision Business-Line as an inventory-management platform for purchasing, warehousing, order processing and reporting. For ecommerce, GDI lists master data, prices, inventory, orders, delivery information and tracking among the relevant exchange objects. A specific Shopify setup only synchronizes the objects its operating model requires. Source: GDI Software on ecommerce integration.
Why use middleware between GDI ERP and Shopify?
Middleware prevents the store from depending directly on the ERP's availability and data model. It receives events, validates them, translates fields and statuses and hands them to the target system in a controlled way. Shopify can therefore remain available when GDI or one interface is temporarily unavailable.
The integration layer also owns rules that do not belong in either standard platform: market and location mapping, payment and shipping mappings, bundle decomposition, status translation or excluding products that must not be sold online. Keeping this logic in one layer makes it traceable and testable.
Which system owns which data?
Every field needs exactly one system of record. Otherwise ERP and store overwrite each other. GDI commonly owns item numbers, operational prices, available inventory and order statuses. Shopify owns customer-facing content, media, metafields, navigation and checkout data. The exact split follows the existing operating processes.
The key integration decision is not the endpoint. It is ownership: which system is allowed to change which value?
Which data flows are typical?
| Object | Typical direction | Key decision |
|---|---|---|
| Products and variants | GDI ERP → middleware → Shopify | Which fields are master data and which remain commerce content? |
| Prices and inventory | GDI ERP → middleware → Shopify | Which price lists, locations and reservations count? |
| Orders | Shopify → middleware → GDI ERP | When is an order ready and uniquely identifiable? |
| Customer and address data | project-specific | How are duplicates, guest orders and consent handled? |
| Fulfillment and tracking | GDI ERP → middleware → Shopify | How are partial shipments and multiple parcels represented? |
| Cancellations and returns | bidirectional by process | Which system triggers posting, inventory and refund? |
How does the integration stay reliable?
Production middleware needs more than successful API calls. Orders must not disappear after a timeout or be created twice after a retry. The architecture therefore needs unique keys, idempotent processing, queues, retry rules, logging and a visible error state.
- Every order receives a unique cross-system reference.
- Failed transfers stay visible and can be repeated safely.
- Mapping and validation errors are separated from temporary connection failures.
- Monitoring checks business completeness, not just technical availability.
- Changes to fields, rules and API versions go through tests and versioned releases.
How does this work at PHARMOS NATUR?
At PHARMOS NATUR, GDI ERP was connected through middleware during the replatforming from Shopware 6 to Shopify Plus. The ERP remains embedded in operational workflows, while Shopify Plus provides the new commerce platform. The integration layer separates these responsibilities and translates the required processes in a controlled way.
This matters because the new store does more than sell products. It connects Green Luxury content, digital consultation, an international setup and a custom app for more than 400 partners. The GDI integration is therefore part of the wider commerce architecture rather than an isolated connector.
How is an integration project delivered?
- Discovery: capture processes, data objects, volumes, exceptions and connected systems.
- Ownership matrix: define source, target, direction and write permissions for each field.
- Mapping: translate IDs, variants, prices, taxes, locations, payments, shipping and statuses.
- Technical build: implement endpoints, queue, validation, logging, retries and monitoring.
- Testing: cover standard cases, partial failures, retries, cancellations, returns and load peaks.
- Cutover: plan the data freeze, final synchronization, acceptance and monitored go-live.
