The verdict in three sentences
A custom B2B e-commerce platform in London costs 40,000 to 150,000 EUR in 2026, depending on catalogue depth, per-customer pricing rules and the level of ERP integration. The realistic timeline runs from 4 to 8 months, and SaaS building blocks (search engine, PIM, payment) add 500 to 3,000 EUR/month in licences. The payback shows quickly: a quick-order portal with multi-user accounts typically lifts average order value by +20 % and frees your sales team from manual entry.
What the budget of a B2B platform covers
B2B is not B2C with a different logo: it demands negotiated pricing, per-customer grids, order approvals, credit limits and fast reordering. Here are the 2026 ranges seen in the London market.
| Line item | 2026 range (EUR) | Note |
|---|---|---|
| Scoping + B2B UX | 6,000 - 15,000 | Pro buyer journey, accounts, roles |
| Catalogue + PIM | 8,000 - 25,000 | Spec sheets, variants, selling units |
| Per-customer pricing engine | 7,000 - 20,000 | Grids, volume discounts, contracts |
| Quick order + reorder | 5,000 - 14,000 | Order by SKU, lists, saved carts |
| ERP/accounting integration | 10,000 - 40,000 | Stock, prices, customers, orders real time |
| Payment + credit terms | 4,000 - 12,000 | Card, transfer, pay-on-terms |
| UAT + go-live | 5,000 - 15,000 | Testing, migration, training |
A mid-size industrial firm with 2,000 SKUs and a per-customer price grid usually lands around 65,000 to 95,000 EUR. A simple catalogue with no ERP stays under 50,000 EUR.
Custom build vs Shopify B2B: the numbers
The boardroom question every time: build custom or capitalise on Shopify Plus (Shopify B2B)? Here is the 3-year comparison.
| Criterion | Custom build | Shopify Plus B2B |
|---|---|---|
| Setup cost | 40,000 - 150,000 EUR | 15,000 - 45,000 EUR (build) |
| Annual licence | 6,000 - 36,000 EUR (SaaS) | 25,000 - 30,000 EUR/yr |
| Per-customer pricing | Unlimited, bespoke | Good, via B2B catalogues |
| Deep ERP integration | Excellent | Fair (apps + API) |
| 3-yr TCO (rough) | 70,000 - 200,000 EUR | 90,000 - 135,000 EUR |
| Timeline | 4 - 8 months | 2 - 4 months |
| Vendor lock-in | Low | High |
Simple rule: under 1.5 M EUR targeted online revenue with standard needs, Shopify Plus is often cheaper in year one. Beyond that, or with complex pricing logic and a central ERP, custom wins back on TCO and autonomy.
Mini case study
Thomas, sales director of an industrial supplies distributor in London, manages 1,800 pro customers and a 420 EUR average order. His 6 reps spend 30 % of their time keying in orders received by email or phone. He invests 78,000 EUR in a custom platform with quick order and ERP integration.
Result over 12 months: average order rises to 504 EUR (+20 %), and 45 % of orders shift to self-service on the portal. On 12,000 orders/year, the order-value gain represents 1,008,000 EUR in additional revenue, and reps recover the equivalent of 1.8 FTE redirected to prospecting. The investment is paid back in under 4 months on the additional margin alone.
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FAQ
How much does a B2B e-commerce platform cost in London in 2026?
Between 40,000 and 150,000 EUR for a custom build. A median project with per-customer pricing and ERP integration sits around 65,000 to 95,000 EUR.
How long does the project take?
Expect 4 to 8 months depending on catalogue and integration complexity. A minimum viable online-ordering release can ship in 3 months, then grow in batches.
Should I choose Shopify Plus or custom?
Shopify Plus (25,000-30,000 EUR/yr) covers standard needs. Custom becomes more cost-effective beyond a certain pricing complexity and high online revenue, thanks to better 3-year TCO.
What order-value uplift should I expect?
On average +20 % once quick order and multi-user accounts are live, because customers reorder more often and outside office hours.
What licence and maintenance budget should I plan?
500 to 3,000 EUR/month in SaaS licences, plus 10 to 15 % of build cost per year for maintenance and enhancements.
Let's scope your project. Share your catalogue, per-customer pricing logic and ERP, and we will price the custom build and the Shopify Plus alternative side by side. 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.