The verdict in three sentences
A custom B2B e-commerce platform in London costs, in 2026, between 45,000 and 90,000 EUR excl. VAT as an initial project, discovery included, for a headless front end and a full order back office. A packaged B2B suite (licence) runs around 12,000 to 25,000 EUR/year, but you own neither the code nor the business logic. Custom becomes worthwhile the moment your negotiated pricing, approval workflows and ERP integrations step outside the standard — which is true for almost every wholesaler and manufacturer.
The real budget, line by line
A B2B platform is not a storefront: it manages customer accounts, per-buyer price grids, hierarchical approvals and quick reordering. Here is the breakdown of a typical 2026 project, in EUR excl. VAT.
| Line item | Scope | 2026 range (EUR excl. VAT) |
|---|---|---|
| Discovery + functional specs | Workshops, journeys, prioritised backlog | 6,000 - 12,000 |
| Headless front end (Next.js) | Catalogue, search, cart, PWA | 18,000 - 30,000 |
| Order / account back office | Negotiated pricing, approval, history | 15,000 - 28,000 |
| Payment + invoicing integration | Stripe/PSP, transfer, instalments | 4,000 - 9,000 |
| QA, testing, go-live | Testing, training, launch | 5,000 - 11,000 |
| Total initial project | 48,000 - 90,000 |
On top comes application maintenance (AMS): between 800 and 2,500 EUR excl. VAT/month depending on SLA and pace of change. The kick-off deposit sits between 30 and 40 %, with the balance staged per delivered milestone.
Custom vs annual licence: the 3-year TCO
The real trade-off is not the headline price but the total cost of ownership. A one-off amortises; a licence is paid every year, forever.
| Scenario | Yr 1 | Yr 2 | Yr 3 | 3-year total (EUR excl. VAT) |
|---|---|---|---|---|
| Custom (65,000 + AMS 1,500/mo) | 83,000 | 18,000 | 18,000 | 119,000 |
| Packaged suite (licence 20,000/yr + setup 15,000) | 35,000 | 20,000 | 20,000 | 75,000 |
| Packaged high volume (licence 35,000 + apps 8,000) | 43,000 | 43,000 | 43,000 | 129,000 |
Below a certain volume, the licence wins over 3 years. Above it — deep catalogues, multiple price grids, heavy traffic — licence tiers and add-on apps catch up and overtake custom, while never making you the owner of the asset.
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Mini case study
Claire, CFO of an industrial-supplies wholesaler in London, processes 1,200 orders/month, 40 % still keyed in by hand by the sales-admin team. Each manual order costs about 11 EUR (agent time + errors). By digitising, she targets -70 % manual entry: 336 automated orders/month, about 3,700 EUR/month saved, 44,400 EUR/year. On a 65,000 EUR custom project, payback lands in around 18 months, after which the gain is net every year.
FAQ
Why not just buy a packaged B2B suite? Because your business rules (per-account pricing, free-shipping thresholds, approvals) quickly exceed the standard: you then pay custom development on top of the licence, stacking both costs. The tipping point is often around 300,000 EUR of annual GMV.
What timeline should I plan for? Count 4 to 7 months from kick-off to production, depending on the number of integrations (ERP, carriers, PSP). An MVP shippable in 3 months is possible by staging secondary features.
What deposit and payment schedule? A 30 to 40 % deposit at kick-off, then payments per delivered milestone. This aligns your cash flow with value actually produced.
Do I own the code? Yes — with custom, the code and database are yours. You can switch providers without starting over, the opposite of a proprietary suite.
How much is maintenance afterwards? AMS ranges from 800 to 2,500 EUR excl. VAT/month: fixes, version upgrades, small enhancements and monitoring. Budget it into your TCO from day one.
Let's scope your project. Tell us your order volume, price grids and ERP integrations: we scope an MVP and a target, with an indicative budget range. 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.
