Three Systems, One Source of Truth

The challenge

The webshop, ERP and accounting software operated as three separate islands. Orders were manually re-entered, stock was synced weekly and invoices were created by hand. Three employees spent half their time just moving data between systems.

Our approach

Bidirectional API integration between Shopify, Exact Online and Billit. Orders are automatically imported into the ERP, stock changes synchronize in real time and invoices are generated and sent automatically.

1. Phase 1

   Map the three islands

   Shopify, Exact Online and Billit each kept their own version of the truth. We documented which system should be authoritative for which data: one decision that prevents half of all integration problems later.

2. Phase 2

   Read orders in automatically

   Every web order lands in the ERP within minutes, including customer details, discounts and shipping method. Errors from retyping disappeared entirely.

3. Phase 3

   Synchronise stock bidirectionally

   This is the delicate part: if the webshop sells something no longer physically in stock, you get unhappy customers. Synchronisation runs both ways and accounts for reserved stock.

4. Phase 4

   Close the invoicing loop

   Invoices are generated and sent automatically once an order ships. Accounting gets an unbroken chain from order to payment, without manual intervention.

The results

• 16 hours/week saved on manual data transfer
• Stock accuracy improved from 71% to 99.4%
• Invoice processing fully automated
• €38,000 in annual personnel cost savings

Frequently asked questions

What if one of the three systems is replaced later?

That is why we connect through an intermediate layer rather than wiring systems directly together. Replace one system and you adjust one connection instead of everything.

How often is stock synchronised?

Real-time on every mutation in this case. For slower-moving stock an interval of a few minutes often suffices and reduces load on the systems.

Does this also work with WooCommerce or Magento instead of Shopify?

Yes. All common webshop platforms offer an API. The principle stays identical; only the connector differs.

What happens if one system goes down?

The connector queues messages and processes them once the system is reachable again. No order is lost during temporary outages.