The verdict in three sentences
A custom B2B e-commerce platform costs between 45,000 and 130,000 EUR in 2026, versus 500 to 3,000 EUR/month for a licence such as Shopify Plus or BigCommerce B2B. Custom development pays off when you have per-client negotiated pricing, multi-user accounts with approval flows and a real-time ERP connector. The payoff: up to +30% of orders placed autonomously, without tying up your sales team.
Custom vs licence: the real trade-off
B2B is not B2C with a different tax rate. Your clients expect their commercial terms, their history, their purchase orders. Here are the 2026 orders of magnitude.
| Item | B2B SaaS licence | Custom build |
|---|---|---|
| Upfront cost | 8,000 - 25,000 EUR (setup) | 45,000 - 130,000 EUR |
| Subscription | 500 - 3,000 EUR/month | Hosting 150 - 600 EUR/month |
| Go-live time | 6 - 12 weeks | 18 - 28 weeks |
| Per-client pricing | Standard, limited | Unlimited, tailored |
| ERP connector | Via paid app | Native, real-time |
| Code ownership | No | Yes |
| Annual maintenance | Partly included | 15% of upfront/year |
What drives the invoice up (or down)
The estimate mostly depends on the depth of integration and the number of business rules. A simple catalogue with pay-on-order costs far less than a customer credit system wired into your accounting.
| Feature | 2026 range (EUR) | Impact |
|---|---|---|
| Multi-user accounts + roles | 6,000 - 15,000 | Purchase delegation |
| Per-client price lists | 8,000 - 25,000 | No more manual quotes |
| ERP connector (Sage, SAP, Odoo) | 10,000 - 35,000 | Real-time stock and price |
| Quick order / reorder by SKU | 4,000 - 10,000 | Higher average basket |
| Credit limits and deferred payment | 6,000 - 18,000 | Loyalty |
| Order tracking portal | 5,000 - 12,000 | Fewer support calls |
Mini case study
Thomas, sales director at an industrial supplies distributor in Nantes, manages 420 professional accounts. His 6 reps spend on average 2 hrs/day keying in orders received by email or phone. He invests 68,000 EUR in a custom platform with per-client pricing and a Sage connector.
After 6 months, 35% of orders are placed autonomously via the portal. That frees roughly 1,900 hrs/year of sales time (6 x 2 hrs x 220 days x 35%), equal to about 58,000 EUR of time redeployed to prospecting. Maintenance runs at 10,200 EUR/year (15%). ROI is reached in around 16 months, not counting the observed basket increase.
FAQ
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Why does a B2B platform cost more than a B2C site?
Because the commercial logic is richer: negotiated pricing, credit limits, hierarchical order approval, ERP integration. These business rules often make up 40 to 60% of the development budget.
Can we start on a licence then migrate to custom?
Yes, and it is a prudent path. Many SMEs validate the market on a B2B licence (500 to 3,000 EUR/month) for 12 to 18 months, then move to custom once volume justifies the investment.
How long until go-live?
Expect 18 to 28 weeks for a full custom platform with ERP connector. An MVP focused on quick ordering and per-client pricing can ship in 12 to 16 weeks.
Is the ERP connector essential?
Not at launch, but it quickly becomes critical: without it, displayed prices and stock diverge from your system, causing errors and disputes. Budget 10,000 to 35,000 EUR depending on the ERP.
What annual maintenance budget should we plan?
Roughly 15% of the upfront cost per year, i.e. 7,000 to 20,000 EUR. This covers security, enhancements, ERP compatibility and fixes.
Let's scope your project. Tell us about your catalogue, your ERP and the number of professional clients to serve: we will size a B2B platform at the right level. 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.