The verdict in three sentences
A custom B2B e-commerce platform in London in 2026 costs between 40,000 and 120,000 EUR depending on the number of features (per-customer pricing, quotas, quick order, approval workflows) and the depth of ERP integration. A high-end SaaS like Shopify Plus B2B launches faster but stays limited when your pricing rules and workflows are specific. The real trade-off is not the upfront price but the total cost over 3-5 years and whether the solution truly fits your sales process.
What a B2B platform covers and what it costs
A B2B portal is not a B2C store with a login. It handles multi-user accounts per client company, negotiated price lists, credit limits and quotas, quick order by SKU, quotes, and above all ERP integration (stock, prices, balances in real time).
| Scope | 2026 range (EUR) | Timeline | ERP integration |
|---|---|---|---|
| Essential B2B portal (accounts, customer pricing) | 40,000 - 60,000 | 5 - 6 months | Daily sync (batch) |
| Standard B2B platform (+ quick order, quotas, quotes) | 60,000 - 90,000 | 6 - 8 months | Near real-time sync |
| Advanced B2B platform (+ EDI, multi-warehouse, workflow) | 90,000 - 120,000 | 8 - 10 months | Two-way real-time |
| Annual maintenance | 8,000 - 22,000 / year | ongoing | Monitoring included |
Prices exclude third-party licenses (search engine, CDN) and heavy data migration. Budget 10 to 18% of the project cost per year for evolutive maintenance.
Custom vs SaaS: the decision table
| Criterion | B2B SaaS (Shopify Plus / BigCommerce) | Custom |
|---|---|---|
| Year 1 cost | 28,000 - 45,000 EUR (license + dev) | 40,000 - 120,000 EUR |
| Recurring license | 2,300+ EUR / month | 0 EUR |
| Complex pricing rules | Limited / workarounds | Unlimited, native |
| Deep ERP integration | Via paid connectors | Custom, real-time |
| Time to launch | 3 - 5 months | 5 - 10 months |
| 5-year TCO (indicative) | 165,000 - 320,000 EUR | 90,000 - 200,000 EUR |
Beyond year 2 or 3, the absence of a recurring license often tips the TCO in favour of custom, especially as your order volume and specifics grow.
Mini case study
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Mark, sales director of an industrial supplies wholesaler in London, manages 180 customer accounts with negotiated pricing. His reps spend 40% of their time keying in orders received by email and phone. He invests 72,000 EUR in a standard B2B platform with ERP integration.
Result over 12 months: 25% of orders move online (about 1,800 orders/year with no manual entry). At 12 minutes saved per order, that frees 360 hours across his 4 reps, reallocated to prospecting. Estimated gain: +140,000 EUR in additional revenue in the first year. The project pays back in under 8 months.
FAQ
What is the minimum budget for a real B2B platform? Budget at least 40,000 EUR for a credible portal with customer accounts and negotiated pricing. Below that, you get a patched-up B2C store that will not hold up to your commercial rules.
How much does ERP integration cost? Depending on the system (SAP, Sage, Cegid, Odoo) and the level (batch vs real-time), integration is 8,000 to 30,000 EUR of the budget. Two-way real-time is the most expensive item.
What is a realistic timeline? From 5 to 10 months depending on scope. An essential portal ships in 5-6 months; an advanced platform with EDI and multi-warehouse needs 8-10 months.
Is custom riskier than Shopify Plus? Risk is controlled by splitting delivery into batches every 3-4 weeks. The upside: you avoid paying 2,300+ EUR/month in licensing and the solution fits your process exactly.
What ROI should I expect? Typically +25% of orders online in the first year and a net reduction in sales entry time, usually paid back in 8 to 14 months.
Let's scope your project. Tell us your number of customer accounts, your pricing rules and your ERP: we will quote a B2B portal at the right scope. 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.
