ERP with Amazon Integration

Selling on Amazon as a German Mid-Market company is rarely a stand-alone channel decision. Listings, prices, stock and order flow must reconcile with the ERP that runs the rest of the business, and the tax treatment of cross-border sales through Amazon's European fulfilment network sits at the heart of every audit conversation. This page describes the practical requirements for an ERP-to-Amazon integration in the DACH context: which APIs matter, how fulfilment models change the integration scope, which ERPs are known for strong Amazon support, and how OSS, IOSS and the German KassenSichV interact with Amazon flows.

FBA versus seller-fulfilled fulfilment

The choice between Fulfilment by Amazon (FBA) and seller-fulfilled prime (SFP) or merchant-fulfilled network (MFN) shapes the integration substantially. Under FBA the ERP must reconcile inventory levels held in Amazon's fulfilment centres across multiple European countries, ingest FBA settlement reports for revenue and fee recognition, and track the Pan-European FBA programme's cross-border stock movements for VAT registration purposes. Under seller-fulfilled models the ERP-warehouse-management combination must handle Amazon-grade shipping cut-offs, return labels and the prime delivery promise. Most established DACH e-commerce ERPs — plentyOne, JTL-Wawi, Xentral, weclapp, billbee — cover both models, but the operational maturity differs and should be evaluated with reference customers in the same fulfilment model.

From MWS to SP-API

Amazon has migrated its third-party seller interface from the legacy Marketplace Web Service (MWS) to the modern Selling Partner API (SP-API), with full deprecation of MWS for most operations completed. SP-API uses OAuth 2.0 and AWS Signature Version 4, exposes a broader set of operations including catalogue, listing, inventory, order, finance and reports, and applies per-application rate limits. Buyers evaluating an ERP's Amazon connector should verify SP-API coverage rather than legacy MWS support, ask which Amazon regions and marketplaces are certified, and confirm that the connector handles bulk operations through the reports API rather than polling individual order endpoints, which is operationally fragile at higher volumes.

Inventory sync and repricing

Inventory synchronisation is the most operationally critical part of the integration: an oversell on Amazon damages account health metrics and can trigger listing suppression. Mature integrations push stock levels at a frequency calibrated to channel velocity and reserve buffer stock for high-velocity SKUs. Repricing is typically handled either inside the ERP (rule-based) or by a specialist repricer such as RepricerExpress, BuyBoxBuddy or sellerboard that consumes ERP cost data and writes prices back via SP-API. Multi-channel sellers should be explicit about which system owns prices: an ERP that overwrites repricer changes on the next inventory cycle creates a problem that takes weeks to diagnose.

VAT, OSS and the German tax context

Cross-border sales through Amazon's European fulfilment network create VAT obligations that the ERP must support. Since July 2021 the OSS (One Stop Shop) regime allows EU sellers to declare intra-EU distance sales centrally; IOSS covers low-value imports from outside the EU. Pan-European FBA may still trigger local VAT registration in the countries where stock is held. The ERP must therefore tag every Amazon transaction with the correct country-of-consumption, distinguish between B2C and B2B (which retain reverse-charge treatment) and produce reconciliations suitable for the OSS quarterly return filed via the German Federal Central Tax Office (BZSt). Note that KassenSichV does not apply to Amazon e-commerce flows directly — it targets cash-register systems — but sellers operating physical stores alongside Amazon must keep the two flows separated for compliance purposes.

Häufig gestellte Fragen

Which ERP is best suited for Amazon FBA?

That depends above all on order volume and complexity and cannot be answered across the board. For beginners with manageable volumes, lean multichannel tools such as Billbee or DreamRobot are widespread, while in the mid segment Actindo, 4SELLERS or JTL-Wawi are frequently named. For large, internationally operating brands, enterprise systems such as Oracle NetSuite with multichannel add-ons come into question. What matters is less the name than whether the system offers genuine FBA functions such as inbound shipping and fee reconciliation, or just a simple marketplace sync.

Does the old Amazon MWS API still work?

No, the old Marketplace Web Service (MWS) has been fully shut down by Amazon. The core areas Orders, Reports and Merchant Fulfillment were already discontinued on 31 August 2023, and the remaining MWS sections followed on 1 April 2024. All current ERP vendors must therefore use the Selling Partner API (SP-API), which Amazon introduced in 2020 as the modern REST successor. When selecting a system, make sure the vendor actively maintains the SP-API and responds promptly to changes.

How does authentication via the Amazon SP-API work?

The SP-API uses Login with Amazon (LWA) as an OAuth 2.0 procedure instead of the earlier static token exchange. The seller authorises the ERP vendor's application once in Seller Central, whereupon a long-lived refresh token is issued, from which the software continuously generates short-lived access tokens. Each access token is valid for only about one hour and is renewed automatically. Important in practice: the granted authorisation generally has to be renewed every 365 days, which is why a well-maintained ERP should remind the seller of the re-authorisation in good time.

Can an ERP also manage FBA stock correctly?

Yes, capable multichannel ERPs separate the FBA stock in Amazon's fulfilment centres from your own warehouse stock and map inbound shipments — the deliveries to Amazon — directly in the system. Added to this is the tracking of returns, refunds and storage fees via the Reports and Finances interfaces of the SP-API. This scope of functionality is a key difference between a simple connector that merely synchronises stock levels and a genuine FBA integration. The exact setup varies considerably with the industry, company size and customisation depth of the specific ERP setup.

How are Amazon fees posted in the ERP?

The SP-API provides all relevant fees via settlement reports and the Finances API, so an ERP can assign them for accounting purposes. These include the referral fee, which differs by product category and in many common categories lies roughly between 8 and 15 percent of the sale price (with outliers above and below depending on the category), plus, for FBA, additional fulfilment, storage and, where applicable, long-term storage fees. A clean integration assigns each item to the appropriate revenue or cost account instead of just taking over the net payout amount. Since Amazon adjusts individual fee rates several times a year, regular automated reconciliation is important to assess margins realistically.

How much does an Amazon interface in the ERP cost?

The range is wide and depends heavily on the chosen system. With modern cloud ERPs and lean multichannel tools, the Amazon integration is often included in the standard package or costs roughly 30 to 150 EUR per month extra, while full-scale multichannel packages tend to run at several hundred euros per month. With classic mid-market and enterprise ERPs, by contrast, four- to five-figure setup costs plus ongoing licences are frequently added. As a rough cross-project guide, pure licence fees often make up only around 25 to 35 percent of total costs, with the larger share going to implementation, customisation, training and data migration.