Integrating your store with fulfillment: Shopify, WooCommerce, OpenCart

Integrating your online store with a fulfillment operator means connecting the two platforms so that every sale automatically becomes a dispatch order in the warehouse system, and the tracking number automatically flows back to your customer. No file exports, no copying addresses by hand. That automation is what eliminates transcription errors and makes next-business-day dispatch possible.

This guide explains what the integration does, how it works on the main platforms and what to prepare on your side. For the broader picture of the service, see what order fulfillment is.

What exactly does a fulfillment integration do?

At minimum, three automatic flows. Orders travel from the store to the warehouse: every paid sale creates a dispatch order in the operator's software, with items, quantities and address. Tracking makes the return trip: when the order ships, the tracking number is written back to the store order, which notifies the customer. And stock stays in sync: the warehouse inventory levels are reflected in the store, so you never sell what no longer exists.

More complete integrations add intermediate statuses (preparing, shipped, delivered), returns flows and the mapping of composite SKUs, such as bundles and kits.

How it works on each platform

Shopify

Integration runs through an app or a private API. Paid orders enter the operator's system in real time via webhooks, and fulfillment is marked automatically in Shopify with tracking attached. The customer gets Shopify's own order-shipped email without anyone touching a thing.

WooCommerce

Here the connection runs through a plugin or the WooCommerce REST API. Since WooCommerce lives inside your WordPress, it matters that the operator handles authentication and webhooks properly. It is worth asking for references of WooCommerce integrations already in production.

OpenCart

OpenCart has fewer ready-made integrations on the market than Shopify or WooCommerce, and this is where many operators fall short. OrderNau built its own OpenCart integration, including order sync and automatic tracking updates, precisely because many Portuguese stores still run on this platform.

Marketplaces: Amazon, eBay and Vinted

Marketplaces play by their own rules: tight dispatch deadlines, mandatory tracking formats and, in Vinted's case, deliveries to specific pickup points. An operator with these integrations live protects your account from suspensions over delays or invalid tracking.

What to prepare before integrating

The technical part is rarely the obstacle; how well the catalogue is prepared decides whether the integration takes days or drags on. Before starting, confirm these points:

• Consistent SKUs: every product variant with a unique code, identical in store and warehouse. Duplicate or missing SKUs are the top cause of errors.
• Weights and dimensions filled in on the store, for correct shipping calculation.
• Kit mapping: if you sell bundles (three soaps under one SKU, say), define the composition so picking is correct.
• Shipping rules: which service to use per destination and order value, from economy to express, with or without pickup points.
• Technical access: API credentials or plugin installation, a step the operator normally guides.

How long does it take?

With a well-prepared catalogue, the technical connection is quick: typically a few days, including tests with real orders, rather than weeks. What delays integrations is rarely the tech; it is SKU clean-up and shipping-rule definition. If you want a fast start, begin there.

The mistakes we see most often

The classic one is going live without test orders. Place two or three real orders and follow the full cycle to delivery before opening the doors. Another common miss is forgetting exception states: paid-then-cancelled orders, incomplete addresses, out-of-stock items. Define what happens in each case before it happens.

On marketplaces, watch the tracking field: a number in the wrong format or field counts as not shipped, with the penalties that follow. And during sales peaks such as Black Friday, it is stock sync that prevents overselling and mass cancellations.

Frequently asked questions

Do I need a developer to integrate?

Usually not. On the main platforms the operator installs and configures; you provide access and validate the tests.

Can I integrate more than one store?

You can. Multiple channels, such as your own store, Amazon and eBay, can converge on the same physical stock, with inventory synced across all of them.

What if my platform is less common?

Just ask. At OrderNau we integrate the main platforms and assess others case by case. Talk to us and we will tell you what is possible.

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Want to see your store's integration running before you decide? Request a demo from OrderNau and we will tell you exactly what your platform needs.