Integrations in e-commerce

In online retail, shop, inventory management, accounting, payment provider and shipping are linked. Every order touches all five. Ready-made plugins often cover the standard well. A custom integration pays off when several channels, payment reconciliation, returns or special prices come into play and data otherwise has to be maintained by hand.

Typical system landscape

Typical data flows

1. Order becomes a sales order on receipt
2. Stock is reconciled every 15 minutes
3. Items and prices are reconciled hourly
4. Shipping status is reported back with the tracking number on dispatch

1. Invoice becomes a posting record daily
2. Credit note from a return is posted daily
3. Payout and fee are matched daily

The intervals are examples. We set them according to your order volume and your tax advisor's requirements. The sequence matters: only once an order exists in the inventory management system is the invoice created there, and only then does the posting go to your tax advisor. Each step builds on the previous one.

Typical problems

• Overselling

  Stock in the shop lags behind the inventory management system. With several channels, the same goods are sold twice.

• Open items

  Payment providers pay out in batches and deduct fees. In accounting, the payment then matches no invoice.

• Returns

  Refunds in the shop are not handed over as credit notes. Revenue and stock no longer add up.

• Manual exports

  Monthly exports to your tax advisor cost time and arrive late. Errors surface only at closing.

• Lost events

  Shopify itself states that webhooks do not always arrive. Without a reconciliation run, orders go missing silently.

How to tell that an integration pays off

A plugin is often the right start. As soon as one of these points applies, a custom connection deserves a look:

• Someone transfers data by hand every week or corrects exports before they go to your tax advisor.
• You sell through several channels, and stock is not right everywhere.
• Your tax advisor regularly asks about missing receipts or unexplained payments.
• The plugin does not know your special cases, such as sets, pre-orders or deviating tax rates.
• An error in the transfer is noticed only weeks later because nobody reports it.

In the free integration check (30 minutes), we go through your systems and workflows. After that you know whether a plugin is enough or which connection we would build.

Examples of connections

• Shopware with JTL-Wawi: orders, stock and products
• Shopware with Business Central: shop to a Microsoft ERP
• Shopify with DATEV and Shopware with DATEV: postings and receipts to your tax advisor
• Shopify with Lexware Office: invoices and credit notes
• JTL-Wawi with DATEV: posting batches from inventory management

What we build

We program the connection between two systems directly, with no platform in between. Every order, every posting and every error is logged. Failed records are retried, and we get in touch on persistent errors. The code belongs to you. On request, we run operation as a subscription you can cancel monthly, with hosting in Germany. More under shop-ERP integration and DATEV integration.

Updated: 10/20/2026