The verdict in three sentences
A custom B2B ecommerce platform in Paris costs between 30,000 and 120,000 EUR excl. VAT in 2026, with the range driven mainly by ERP integration and customer-specific pricing. Expect a 4-to-8-month timeline for a full production launch with quick ordering, multi-buyer accounts and credit terms. The return on investment hinges on lower order-processing cost, often cut to a third of manual order entry.
Cost per functional module
B2B is not B2C with a different logo: pricing rules, approvals and IT-system integration carry the weight. Here is a 2026 order of magnitude per building block, excluding hosting.
| Module | 2026 cost (EUR excl. VAT) | Indicative time |
|---|---|---|
| Catalog core + pro accounts | 8,000 - 18,000 | 4 - 6 weeks |
| Customer pricing / negotiated tiers | 6,000 - 15,000 | 3 - 5 weeks |
| Quick order (SKU + quantity) | 4,000 - 9,000 | 2 - 3 weeks |
| ERP integration (stock, price, orders) | 10,000 - 35,000 | 6 - 12 weeks |
| Credit and deferred payment | 5,000 - 14,000 | 3 - 5 weeks |
| Multi-buyer approval workflow | 4,000 - 11,000 | 2 - 4 weeks |
| Support portal and delivery tracking | 3,000 - 10,000 | 2 - 4 weeks |
A Starter project stays under 40,000 EUR excl. VAT when the ERP already exposes a clean API; a project where flows must be rebuilt from a legacy ERP quickly climbs toward 100,000 EUR excl. VAT.
What moves the invoice
| Factor | Budget impact | Comment |
|---|---|---|
| Modern ERP with REST API | -20 to -30% | Standard integration, less dev |
| Legacy ERP / flat files | +25 to +50% | Middleware and sync to build |
| Number of pricing tiers | +5,000 per major tier | Complex price rules to test |
| Multi-language FR/EN | +8,000 - 15,000 | Duplicated catalog and content |
| Catalog volume > 20,000 SKUs | +10,000 - 20,000 | Search, filters, perf to harden |
| Order history migration | +6,000 - 12,000 | Data migration and cleanup |
Mini case study
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Marc, sales director of an industrial supplies distributor in Paris, processes 900 orders a month, 70% of which arrive by email or phone. Each manual order takes 12 minutes of a sales-admin's time, about 126 hours a month. By moving 60% of those orders to a portal costing 68,000 EUR excl. VAT, he saves around 75 hours a month, close to 2,250 EUR excl. VAT of monthly admin cost. The project pays back in just over 30 months on the admin line alone, before counting the higher average basket from automated cross-selling.
FAQ
What is the price gap between B2B and B2C? A B2C showcase store starts around 8,000 EUR excl. VAT, while a B2B platform with customer pricing and ERP starts at 30,000 EUR excl. VAT. The complexity comes from business rules, not design.
Can we launch in phases to spread the budget? Yes, a catalog core + pro accounts at 25,000 EUR excl. VAT can ship in 3 months, then you add credit and ERP in phase 2. That avoids locking up 80,000 EUR at once.
How much is annual maintenance? Budget 15 to 20% of the build cost per year, i.e. 6,000 to 20,000 EUR excl. VAT, for hosting, fixes and minor evolutions.
Is ERP integration really mandatory? Not at launch, but without it your teams re-key orders. True B2B ROI comes from near-real-time sync of stock, price and orders.
What is a realistic timeline for a usable V1? Between 4 and 8 months depending on scope; a V1 with quick ordering and customer pricing can go live in 4 months if the ERP cooperates.
Let's scope your project. Share your ERP, your number of SKUs and pricing tiers for an estimate between 30,000 and 120,000 EUR 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.