ERP API Integration for a B2B Ordering Portal: Amsterdam Cost (2026)

The verdict in three sentences

An API connector between Exact Online or SAP Business One and a B2B ordering portal costs EUR 8,000 to 20,000 excl. VAT in Amsterdam in 2026, depending on the number of data flows and the quality of your starting data. The most visible gain is the end of rekeying: 2 to 3 hours of data entry saved per day for the order desk, and reference or pricing errors almost disappear. The real scoping issue is not the technology but error handling and the exchange log, which decide whether the integration holds up over time.

What the connector must do, flow by flow

The CFO of a distributor with 1,100 trade customers expects three things: every order confirmed on the portal lands in the ERP without rekeying, customers see reliable stock, and their credit exposure is checked before confirmation. That translates into six distinct flows, each with its own frequency and direction.

Exact Online exposes a REST API with rate limits (around 60 calls per minute per company), while SAP Business One goes through its Service Layer. Rate limits and the choice of an optional middleware weigh on budget and maintenance, so they must be settled in the scoping workshop.

Budget and timeline: three integration levels

For comparison, an off-the-shelf connector runs around EUR 150 to 400 per month, but it rarely handles per-customer discounts and credit limits, which are precisely the critical points in B2B distribution. Over 5 years, a Standard custom connector costs about EUR 25,000 including maintenance, against EUR 9,000 to 24,000 for a subscription that leaves part of the rekeying in place.

Error handling and exchange log: where reliability is decided

An integration that works 98% of the time still produces around twenty anomalies a month on 1,000 orders. Without tooling, the order desk finds out when the customer calls. The specification should therefore require:

• a timestamped log of every exchange (request, response, status), kept for 12 months;
• a queue with automatic replay when the ERP is unavailable, for example during an overnight backup or an API rate-limit window;
• email alerts after 3 consecutive failures on the same flow;
• a manual replay screen for the order desk, without calling the vendor;
• regression tests rerun at every ERP update.

This foundation represents 15 to 20% of the budget, and it is what stops you calling the vendor every week.

Mini case study

Sanne, CFO of an industrial supplies distributor in Amsterdam, manages 1,100 customers and about 90 portal orders a day, rekeyed into Exact Online by two order desk assistants. Measured time: 2 h 30 per day, about 550 hours a year. At EUR 38 fully loaded hourly cost, rekeying costs EUR 20,900 a year, plus 1.8% of orders with a reference or price error, each costing EUR 50 on average to fix (credit note, return, shipping), roughly EUR 4,000 more. Sanne picks the Standard level at EUR 14,500 with the monitoring option at EUR 2,000. Total investment: EUR 16,500 excl. VAT, maintenance EUR 2,400 a year. Estimated annual savings: EUR 24,900, minus maintenance, EUR 22,500 net. Payback in under 9 months, and the two assistants move to following up unconverted quotes.

FAQ

Do we need to upgrade our ERP before the integration?

Not necessarily. Exact Online is always current; for SAP Business One, a version under 3 years old with the Service Layer enabled simplifies access. An upgrade typically costs EUR 3,000 to 8,000 with your SAP partner and should be scheduled first.

Can the portal reject an order when the credit limit is exceeded?

Yes, that is one of the Standard flows: credit exposure refreshes every 15 minutes and the order goes on hold above the limit. Allow 1 to 2 development days for exception rules.

What happens if the ERP is down overnight?

Orders are stored in a queue and pushed as soon as the ERP is back, with no loss. The exchange log keeps a trace of every replay for 12 months.

How long does the order desk need to learn the monitoring screen?

Half a day of training is usually enough. The manual replay screen resolves 90% of anomalies without technical help.

Can we start with orders and stock only?

Yes, the Essential level at EUR 8,000 to 11,000 delivers those two flows in 6 weeks. The architecture is designed to add credit and pricing later without a rebuild.

Let's scope your project. Send us your list of flows, your ERP and your order volume: we will price a connector between EUR 8,000 and 20,000 with a 6 to 10 week plan. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.