The verdict in three sentences
A wholesaler shipping 600 trade orders a day cannot let its B2B webshop show wrong stock levels twice a week without losing retail and restaurant accounts. A custom API connector between the WMS and the webshop costs 12,000 to 30,000 EUR excl. tax (about 13,000 to 33,000 USD) and ships in 6 to 10 weeks, while an off-the-shelf middleware rents for 300 to 1,500 EUR a month. The right choice depends on how many data flows you need to sync and how good your WMS API is, far more than on the sticker price.
Why webshop stock drifts away from the WMS
In most distribution warehouses we audit, the B2B webshop receives a stock export once or twice a day, often as a CSV file dropped on an FTP server. Between exports, the warehouse keeps picking, receiving and counting. The webshop therefore sells bottles that are already reserved, and customer service spends its mornings calling buyers to announce a stockout.
| Cause of the gap | Observed frequency | Commercial impact |
|---|---|---|
| CSV export 1 to 2 times a day | Daily | Overselling on fast-moving SKUs |
| Picking reservations not passed on | 2 to 3 times a week | Orders accepted with no available stock |
| Supplier receipts keyed in at end of day | Weekly | Products shown out of stock while sitting on the dock |
| Per-customer allocations (en primeur, vintages) ignored | Seasonal | Conflicts with priority accounts |
| Cycle counts not reflected | Monthly | 1 to 4% gaps on some product families |
| No shipping status on the webshop | Permanent | 15 to 25 calls a day to customer service |
The real issue is the frequency and granularity of the exchanges. A well-designed connector pushes available-to-sell stock (physical minus reserved minus allocated) every 5 minutes, or in real time via webhook if the WMS allows it, and sends each order status back to the customer: picked, shipped, carrier tracking number.
Custom connector or middleware: 2026 comparison
| Criterion | Off-the-shelf middleware | Custom API connector |
|---|---|---|
| Upfront cost | 2,000 to 8,000 EUR excl. tax for setup | 12,000 to 30,000 EUR excl. tax |
| Recurring cost | 300 to 1,500 EUR a month | 150 to 400 EUR a month for hosting and monitoring |
| Time to go live | 3 to 6 weeks | 6 to 10 weeks |
| Sync frequency | 5 to 15 minutes depending on plan | Real time or every 5 minutes |
| Business rules (allocations, en primeur, excise duties) | Limited to standard fields | Coded to your rules |
| Dependency | Vendor and its available connectors | Source code you own |
| 3-year cost (order of magnitude) | 13,000 to 62,000 EUR excl. tax | 17,000 to 45,000 EUR excl. tax |
Middleware wins when your WMS and your e-commerce platform are already in its connector catalog and your rules stay standard. Custom work pays off as soon as you manage per-customer allocations, excise duties, multiple pack formats (bottle, case of 6, pallet) or an older WMS without a clean REST API.
Target architecture and budget per work package
The architecture we recommend relies on an independent integration layer: it reads the WMS, transforms the data, pushes it to the webshop and keeps a log of every exchange. If the webshop goes down, messages wait in a queue and are replayed. If the WMS returns an error, an alert goes to the logistics team before customers see it.
| Work package | Scope | Indicative budget EUR excl. tax | Duration |
|---|---|---|---|
| Scoping and flow mapping | Field inventory, available-stock rules, WMS API tests | 2,000 to 4,000 | 1 to 2 weeks |
| Stock and price flow | Available stock every 5 minutes, prices per customer grid | 4,000 to 9,000 | 2 to 3 weeks |
| Order flow | Order creation in the WMS, reservations, rejection handling | 3,000 to 8,000 | 2 weeks |
| Status and tracking | Picked, shipped, carrier number, customer notification | 2,000 to 5,000 | 1 to 2 weeks |
| Monitoring and replay | Message queue, log, alerts, dashboard | 1,000 to 4,000 | 1 week |
The total ranges from 12,000 to 30,000 EUR excl. tax depending on the quality of the WMS API. A WMS that only exposes a database or flat files adds 20 to 30% to the budget.
Mini case study
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Daniel, logistics director of a wine and spirits wholesaler in Toronto, ships 600 trade orders a day with an average basket of 420 EUR. With a connector synced every 5 minutes, he expects to avoid 3% of orders hitting a stockout, i.e. 18 orders a day. If 20% of those orders were lost for good, that is 1,512 EUR of revenue a day, or about 378,000 EUR over 250 working days. With a 22% gross margin, the gain reaches 83,000 EUR a year. For a 24,000 EUR connector and 3,000 EUR of yearly monitoring, payback comes in about 4 months, before counting the 15 to 25 daily customer service calls saved.
FAQ
Our WMS has no REST API, is a connector still possible?
Yes, through database reads, flat files or a middle service installed at the vendor. Expect 20 to 30% more budget and a sync every 5 to 10 minutes rather than real time.
Should we sync in real time or every 5 minutes?
For 600 orders a day, a 5-minute sync is enough for 95% of SKUs. Real-time webhooks make sense for very fast movers or flash sales of en primeur wines.
How long does it take to go live?
Between 6 and 10 weeks, including 1 to 2 weeks of scoping and 1 week of acceptance testing alongside the old flow. Ideally the switch happens outside the holiday season, which often carries 30 to 40% of yearly volume.
Who maintains the connector after delivery?
A maintenance contract covers monitoring, fixes and WMS API version upgrades. These contracts generally sit between 150 and 400 EUR excl. tax a month depending on the number of flows.
Does the connector handle excise duties and customer allocations?
Yes, provided they are described during scoping. These rules often add 2 to 3 days of development, but they prevent most disputes with priority accounts.
Let's scope your project. Send us your WMS name, your B2B platform and your daily volumes: we price the connector per work package, with an indicative budget and go-live timeline. 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.
