The verdict in three sentences
A custom B2B e-commerce platform costs between EUR 40,000 and EUR 150,000 in 2026 depending on pricing logic, customer accounts and integrations. The line items that inflate a quote are not the design but the per-customer pricing, quick ordering and approval workflows. Before building, settle the key question: does a packaged SaaS (Shopify B2B, BigCommerce) suffice, or do your business rules demand custom development?
What makes up a B2B portal price
B2B is not B2C with a different tax rate. Complexity comes from negotiated price grids, credit limits, multi-buyer accounts and ERP connectivity. Here are the typical line items for a London project in 2026.
| Line item | 2026 range (EUR) | Indicative timeline |
|---|---|---|
| Discovery + B2B UX | 4,000 - 12,000 | 2 - 4 weeks |
| Catalogue + per-customer pricing | 10,000 - 35,000 | 4 - 8 weeks |
| Multi-user accounts + roles | 6,000 - 18,000 | 3 - 6 weeks |
| Quick order / CSV import | 4,000 - 12,000 | 2 - 4 weeks |
| ERP / payment integration | 8,000 - 30,000 | 4 - 10 weeks |
| Testing + go-live | 4,000 - 15,000 | 2 - 4 weeks |
A Starter project (simple catalogue, group pricing) runs around EUR 40,000 - 60,000. A Premium project (individualised pricing, credit limits, real-time ERP, PWA) often exceeds EUR 120,000.
Packaged SaaS or custom build?
The real 2026 trade-off is between a market B2B subscription and a bespoke build. The figures below are orders of magnitude.
| Criterion | Shopify B2B / BigCommerce | Custom build |
|---|---|---|
| Upfront cost | 8,000 - 30,000 EUR | 40,000 - 150,000 EUR |
| Platform subscription | 2,300 - 20,000 EUR/yr | Hosting 1,200 - 6,000 EUR/yr |
| Per-customer pricing | Limited / via lists | Unlimited, fine-grained |
| Approval workflows | Basic | Fully custom |
| ERP integration | Standard connectors | Dedicated API |
| Launch timeline | 6 - 12 weeks | 4 - 8 months |
Simple rule: if your pricing rules fit within lists and customer groups, stay on SaaS. Once pricing becomes contractual and individualised, custom pays off.
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Mini case study
Marc, sales director of an industrial components maker in London, manages 320 trade customers with negotiated discounts from 8 to 34 percent. His reps spend 6 hours a week each (12 people) re-keying orders received by email. Estimated cost: 12 x 6 h x 46 weeks x EUR 28 = EUR 92,736/year of unproductive time. A custom portal at EUR 78,000 automating 60 percent of those orders frees roughly EUR 55,000/year, a payback in under 18 months, before counting revenue gained from 24/7 availability.
FAQ
What minimum budget starts a credible B2B portal? Budget at least EUR 40,000 for a serious foundation with group pricing and customer accounts. Below that you get a disguised B2C without the essential B2B workflows.
How long does the project take? Between 4 and 8 months depending on integrations. Catalogue and ERP are the two items that stretch the timeline most.
What does maintenance cost? Plan for maintenance of 12 to 18 percent of the initial build per year, i.e. EUR 5,000 to 27,000/year for fixes, evolutions and security.
Can we start on SaaS then migrate to custom? Yes, a common strategy: validate the model on Shopify B2B (6 to 12 weeks), then move to headless once volume and rules justify the investment.
How much is B2B payment integration? Between EUR 4,000 and EUR 12,000 for transfer, card and payment-on-terms; more if you add factoring or B2B split payment.
Let's scope your project. Tell us about your catalogue, your per-customer pricing logic and your ERP integrations for a precise estimate. 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.