B2B Wholesale E-commerce Platform Cost in London (2026 Buyer's Guide)

The verdict in three sentences

A custom B2B portal for a wholesaler costs between 45,000 and 120,000 EUR in 2026, while Shopify Plus starts at 2,300 EUR/month with limits on per-customer pricing and approval workflows. The decision hinges on your pricing complexity: volume discount grids, multi-buyer accounts and quick order justify going custom. An average B2B order value climbing +23% after a rebuild pays back the investment in 12 to 20 months.

B2B SaaS vs custom headless: the numbers

Both routes answer the same need — selling to professionals at negotiated prices — but the economics diverge sharply based on your volume and pricing rules.

In practice, a wholesaler with fewer than 200 accounts and simple pricing is better off on SaaS. Above 500 accounts, tiered discounts and order approval logic, custom becomes worthwhile.

What the custom budget actually covers

A B2B portal quote breaks into precise line items. Here is a representative split for a 72,000 EUR project.

The day rate of a specialised B2B e-commerce agency sits between 550 and 700 EUR in 2026. Expect a project manager, a backend developer, a front-end integrator and a half-time UX role over 14 to 22 weeks.

Mini case study

Nicholas, sales director of an electrical wholesale firm in London, manages 640 trade accounts with negotiated discounts of 8 to 22%. His old brochure site drove 60% of orders by email and phone, tying up 3 half-time reps on data entry.

He invests 68,000 EUR in a custom portal with per-account pricing, SKU quick order and one-click reorder. Result over 12 months: average B2B order value +23% (from 340 to 418 EUR), 45% of orders shifted to self-service, and 1.5 FTE freed for prospecting. The admin saving alone (~48,000 EUR/year of sales time) repays the project in 17 months, before any revenue uplift.

FAQ

What is the minimum budget for a real B2B portal in 2026?

Expect 45,000 EUR for a credible custom foundation (per-customer pricing, buyer accounts, quick order). Below that, Shopify Plus B2B at 2,300 EUR/month stays more rational.

How long to deliver?

Between 14 and 22 weeks for custom headless, versus 6 to 10 weeks for configured SaaS. ERP integration is the item that stretches the timeline most.

What is the ongoing maintenance cost?

Between 12 and 18% of the initial cost per year, i.e. 8,600 to 21,600 EUR/year for a 72,000 EUR project. This covers fixes, version upgrades and minor evolutions.

Does custom really avoid transaction fees?

Yes: a headless build removes the 0.15 to 0.5% Shopify charges. On 3M EUR annual volume, that saves 4,500 to 15,000 EUR per year.

Can we start on SaaS then migrate?

Yes, it is a prudent strategy: validate the model on Shopify Plus for 12 to 18 months, then move to headless once pricing limits block growth.

Let's scope your project. Tell us your account volume, discount rules and ERP: we frame the scope (SaaS vs custom) and an indicative budget between 45,000 and 120,000 EUR. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.