The verdict in three sentences
A clean ERP-to-B2B-site integration costs 12,000 to 35,000 EUR depending on the ERP and the volume of flows to synchronise. The most underestimated line is not the connector but error handling, logging and reconciliation, which separates a reliable site from a catalogue showing wrong stock levels. Budget 8 to 12 weeks from scoping to monitored go-live.
The line-by-line cost breakdown
In Rotterdam as across the Randstad, a B2B distributor wanting real-time stock, customer-specific pricing and order status on its site pays mostly for the robustness of the data flows, not for the interface. Here is the 2026 order of magnitude for a serious integration.
| Line item | 2026 range (EUR) | What it covers |
|---|---|---|
| ERP connector (by system) | 8,000 - 20,000 | Products, stock, pricing, customers |
| Real-time sync via API | 5,000 | Webhooks / polling, queues |
| Error handling, logs, monitoring | 3,000 | Alerts, replays, flow dashboard |
| Mapping and business rules | 2,500 | Customer pricing, discounts, units |
| Testing and staging environment | 2,500 | Test data set, load testing |
| Project total | 21,000 - 33,000 | Excluding annual maintenance |
The connector cost depends heavily on the ERP. An open ERP with a documented API lowers the bill; a closed or legacy system raises development time.
| ERP | Integration complexity | Connector (EUR) |
|---|---|---|
| Sage 100 / Sage X3 | Medium, API and web services | 8,000 - 14,000 |
| Cegid | Medium to high | 10,000 - 16,000 |
| SAP Business One | High, connector licences | 14,000 - 20,000 |
| In-house / legacy ERP | Very high, reverse engineering | 15,000 - 22,000 |
| Odoo / open-source ERP | Low, native REST API | 6,000 - 10,000 |
Middleware vs direct integration
Two architectures compete. Direct integration links the site to the ERP point-to-point: cheaper upfront, but fragile as soon as a third system appears. Middleware (an integration bus or iPaaS) centralises flows: more expensive, but scalable and far easier to supervise.
| Criterion | Direct integration | Middleware / iPaaS |
|---|---|---|
| Upfront cost | 12,000 - 22,000 EUR | 20,000 - 35,000 EUR |
| Monthly cost | 0 - 150 EUR | 250 - 900 EUR (iPaaS licence) |
| Adding a 3rd system | Costly, rewiring | Simple, new flow |
| Flow supervision | To be built | Included |
| Recommended if | 2 systems, stable flows | 3+ systems, growth |
For a distributor with only ERP + site, direct integration is enough. As soon as a CRM, a WMS or a marketplace joins, middleware pays off.
Mini case study
Sarah, COO of an industrial supplies distributor in Rotterdam, manages 4,200 SKUs in Sage X3. Her sales reps spent 6 hours a week checking stock by phone before confirming orders, and 4% of web orders shipped against wrong stock, generating credit notes and disputes.
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She chooses a direct Sage X3-to-B2B-site integration at 24,000 EUR, delivered in 10 weeks. Result: stock syncs every 5 minutes, customer pricing is automatic. The 6 weekly verification hours vanish (about 1,250 EUR/month of sales time recovered) and wrong-stock orders fall below 0.5%. Estimated payback in 16 months, before counting the disputes avoided.
FAQ
How much is annual maintenance for an ERP integration?
Budget 12 to 18% of the project cost per year, i.e. roughly 2,500 to 5,000 EUR for a 24,000 EUR integration. It covers API changes, ERP version upgrades and incident support on the flows.
Can you sync in real time or only in batches?
Both exist. Real time (webhooks) costs around 5,000 EUR more but avoids wrong stock; batches (hourly or overnight) are enough for stable catalogues and cost less.
What is a realistic timeline from order to go-live?
8 to 12 weeks for a standard integration: 2 weeks of scoping and mapping, 4 to 6 of development, 2 to 3 of testing and monitored go-live. An in-house or legacy ERP stretches everything.
Do we need an extra licence on the ERP side?
Often yes, especially SAP Business One which charges for a connector or API calls. Budget 1,000 to 4,000 EUR/year in licences on top of development depending on the vendor.
What happens if the ERP goes down?
A good integration queues flows and automatically replays them on recovery, with an alert to the team. That is exactly what the 3,000 EUR of error handling buys: preventing the site from showing stale data without anyone noticing.
Let's scope your project. Tell us your ERP (SAP, Sage, Cegid, Odoo), the number of SKUs and the flows you need (stock, pricing, orders): we scope the perimeter and an indicative budget between 12,000 and 35,000 EUR. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
