The verdict in three sentences
Integrating an e-commerce site with ERP and stock management costs between 10,000 and 35,000 EUR in 2026 depending on the number of flows and the freshness required (real time or batch). The main gain is not automation but reliability: fewer oversells, fewer cancellations, and a support team no longer spending its days fixing discrepancies. ROI is measured on three fronts: saved orders, admin hours saved and customer satisfaction.
What you actually integrate
An e-commerce/ERP integration is never a single flow. You sync stock, prices, product records, orders and sometimes invoices. Each flow has its own frequency and criticality.
| Synced flow | Direction | Recommended frequency | Criticality |
|---|---|---|---|
| Stock levels | ERP to site | Real time / 5 min | Critical |
| Prices and customer tariffs | ERP to site | Hourly | High |
| Product records and media | ERP to site | Daily | Medium |
| Orders | Site to ERP | Real time | Critical |
| Shipping statuses | ERP to site | Real time | High |
| Invoices / credit notes | ERP to site | Daily | Medium |
Real-time stock sync costs the most, but it also returns the most.
Cost by method
Three approaches exist, from a standard connector to custom middleware. The choice depends on the number of systems and the business logic.
| Approach | 2026 cost (EUR) | Timeline | Yearly maintenance |
|---|---|---|---|
| Standard connector (SaaS) | 3,000 - 8,000 | 3-6 weeks | 1,200 - 3,000 |
| Custom API integration | 12,000 - 25,000 | 6-12 weeks | 2,500 - 6,000 |
| Middleware / integration bus | 25,000 - 35,000 | 10-16 weeks | 5,000 - 10,000 |
A standard connector is enough for a common ERP and a simple catalog. As soon as prices are negotiated per customer or multiple warehouses are involved, custom integration becomes necessary.
The hidden cost of stockouts
A B2B e-commerce without synced stock cancels on average 3 to 8 % of its orders due to stockouts. Each cancellation costs processing, a credit note, and above all a customer who will order elsewhere next time. On 2,000 orders/month at 180 EUR, 5 % cancellations means 18,000 EUR of revenue at risk every month.
Mini case study
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Sophie is e-commerce director at a professional-kitchen-equipment wholesaler in Lille: 1,900 orders/month, average basket 210 EUR, 6 % cancellation rate from stale stock. Custom API integration quote: 21,000 EUR, stock sync every 5 minutes. After three months, cancellations drop to 1.8 %, meaning about 120 saved orders/month × 210 EUR = 25,200 EUR/month of recoverable revenue. Add 22 hours/week of manual entry removed. Payback in under two months.
FAQ
Do I really need real-time stock?
For high-volume B2B, yes: a 5-minute sync is enough and prevents 80 % of oversells. Daily sync only suits low-rotation catalogs.
Can a standard connector be enough?
Yes for a common ERP and a simple catalog, from 3,000 EUR. As soon as you handle per-customer pricing, multiple warehouses or reservation rules, you need custom work.
What if the ERP goes down?
A well-designed integration queues flows and replays exchanges on recovery. Without that resilience, you lose orders: demand it in the specification.
How many admin hours are saved?
Between 15 and 30 hours per week for an active catalog, by removing double entry of orders, stock and invoices.
Can multiple warehouses be integrated?
Yes, with multi-site availability and shipping-warehouse selection logic. This usually adds 4,000 to 8,000 EUR depending on the number of sites.
Let's scope your project. Tell us your ERP, order volume and priority flows, and we'll quote an integration with the right sync frequency. 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.
