The verdict in three sentences
A B2B webshop that refreshes stock once a night sells products it no longer has, especially when the catalogue is spread across several warehouses. Real-time sync with availability per warehouse, stock reservation at cart level and a promised delivery date costs EUR 15,000 to 40,000 excl. VAT in 2026. By removing 4 to 6% of cancelled orders, it typically pays back in 8 to 14 months for a mid-sized distributor.
Nightly batch, hourly sync or real time
Most legacy B2B shops import a stock file from the ERP or WMS one to four times a day. Between imports, displayed stock drifts from physical stock, and the gap widens with the number of warehouses and channels (field sales, phone, marketplace). Real time relies on events: every stock movement in the WMS updates the shop within seconds.
| Architecture | Stock freshness | 2026 cost (order of magnitude) | Typical cancellation rate | Best for |
|---|---|---|---|---|
| Nightly CSV import | 12 to 24 h | EUR 3,000 to 6,000 | 6 to 9% | One warehouse, low turnover |
| Hourly API sync | 1 h | EUR 8,000 to 15,000 | 3 to 5% | One or two warehouses |
| Event-driven real time (webhooks, message queue) | Under 30 s | EUR 15,000 to 30,000 | 1 to 2% | Three or more warehouses |
| Real time + cart reservation + delivery promise | Under 30 s | EUR 25,000 to 40,000 | Under 1% | 10,000+ SKUs, high turnover |
| Dedicated OMS middleware (licence) | Under 30 s | EUR 1,500 to 5,000 per month + integration | Under 1% | Multi-country groups |
Cart reservation stops two customers from buying the same last pallet: stock is held for 15 to 30 minutes, then released if the order is not confirmed. The promised date combines available stock, nearest warehouse, picking cut-off time and carrier lead time.
What a cancelled order really costs
The cost of a stockout discovered after ordering goes beyond the lost sale. Someone must call the customer, cancel or edit the order in the ERP, sometimes refund a deposit, and handle a buyer who may switch to a competitor.
| Item | Cost per cancelled order (2026 estimate) | Comment |
|---|---|---|
| Sales admin time (call, ERP edit) | EUR 18 to 30 | 25 to 40 minutes at EUR 45 loaded hourly cost |
| Cancelled partial picking or restocking | EUR 8 to 20 | If the order is already being picked |
| Refund or credit note | EUR 3 to 8 | Bank fees, accounting entry |
| Goodwill discount | 2 to 5% of the order | Common with key accounts |
| Lost margin if the customer leaves | 20 to 30% of the basket | About one customer in three does not reorder |
| Average total for a EUR 900 B2B basket | EUR 90 to 150 | Order of magnitude seen at distributors |
What to include in the specification
Three choices drive the budget. First, the source of truth: the WMS, the ERP or an intermediate OMS, which must publish stock movements via API or webhook. Next, allocation rules: safety stock per warehouse, quotas reserved for certain customers, inter-site transfers. Finally, display: exact quantity, range ("50+") or simple status, and delivery date per order line. An ERP without a usable API (older Sage 100 versions or vertical software) adds EUR 5,000 to 10,000 excl. VAT for a connector.
Mini case study
Sophie, supply chain director at an electrical equipment distributor near Nantes, manages 15,000 SKUs across three warehouses (Nantes, Tours, Bordeaux). The B2B shop handles 2,400 orders a month with an average basket of EUR 900, and 5.5% of orders are cancelled or edited due to stockouts, i.e. 132 orders. At EUR 110 average cost per cancellation, the loss reaches EUR 14,520 a month, about EUR 174,000 a year. The chosen project, event-driven real time with cart reservation and promised date per warehouse, is quoted at EUR 34,000 excl. VAT, plus EUR 6,000 yearly maintenance. The cancellation rate drops to 1%, i.e. 24 orders a month and EUR 31,700 a year. Gross savings reach about EUR 142,000 a year. After the project and maintenance, first-year net gain is close to EUR 102,000, with payback in under 3 months, much faster than average because the starting cancellation rate was high.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
FAQ
Do I need to change ERP to show real-time stock?
Rarely. If the ERP or WMS exposes an API or can emit events, a connector is enough. Otherwise, an intermediate connector adds EUR 5,000 to 10,000 excl. VAT.
How long does the sync take to set up?
Allow 8 to 14 weeks for three warehouses, testing included. The longest phase is defining allocation rules between sites.
Should B2B customers see the exact quantity?
Not necessarily. Many distributors show a range above 50 units to avoid revealing their stock, and the exact quantity below that.
How do you handle a customer ordering from two warehouses?
The shop can split the order into two shipments with two promised dates, or offer to wait for an inter-site transfer. This setup adds EUR 3,000 to 6,000 excl. VAT to the project.
Does stock reservation block field sales reps?
Not if the hold is short, usually 15 to 30 minutes. Reserved stock is visible in the ERP and released automatically if the cart is abandoned.
Let's scope your project. Tell us your warehouses, your ERP or WMS and your order volume: we price real-time sync, reservation and delivery promise, with an indicative budget of EUR 15,000 to 40,000 excl. VAT. 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.