B2B E-commerce Platform: Buy vs Build in London (2026)

The verdict in three sentences

An off-the-shelf platform (BigCommerce B2B, Shopify Plus B2B) launches fast, but its EUR 2,000-5,000/month subscription plus apps and integration eventually catches up to a custom build of EUR 40,000-120,000. For a wholesaler whose pricing logic, credit terms and reseller accounts are the heart of the business, the 3-year TCO is often comparable, but custom keeps the roadmap in your hands. The rule: rent while your needs stay standard, build once your pricing tiers and ERP become the differentiator.

What B2B demands and B2C ignores

A wholesaler doesn't sell like a consumer shop. Baskets run to hundreds of SKUs, every reseller has its own negotiated price, payment terms and sometimes its own catalogue. Here are the non-negotiable functions and their weight in a 2026 project:

The "off-the-shelf" column hides the trap: every ticked box adds a monthly app, and three or four apps turn a EUR 2,000 subscription into a real EUR 3,500.

Buy vs Build: the 3-year TCO

Compare the two paths for a mid-sized wholesaler (300 resellers, 8,000 SKUs, ERP integration). Ballpark 2026 figures, EUR.

Custom pays off beyond 24-30 months, provided scope is stable. Below a one-year horizon or if the need is standard, SaaS stays safer.

Mini case study

Simon, sales director at a catering-supplies wholesaler in London, takes 70% of orders by phone and email. Each order eats 12 minutes of order-desk entry. Across 4,200 orders/month that is 840 hours/month, roughly 5 FTEs at a loaded EUR 2,400. Moving 60% of resellers onto a custom portal (EUR 75,000) frees ~3 FTEs, i.e. EUR 86,400/year in order-desk savings. The project pays back in under 11 months, before counting the drop in entry errors.

FAQ

What does an off-the-shelf B2B platform really cost? Count the base subscription (EUR 2,000-5,000/month) plus EUR 500-1,200/month of B2B apps and EUR 10,000-20,000 of setup. The sticker price is rarely the real cost.

Is custom riskier? The risk is governance, not technology. With delivery in 3-week increments and ERP integrated early, risk is controlled. Expect a 4-8 month timeline.

Can we start on SaaS then migrate to custom? Yes, it's a prudent strategy. Validate the need over 12-18 months on SaaS, then rebuild once business rules stabilise. Catalogue and customer migration costs EUR 8,000-15,000.

What ERP integration should we plan? At minimum real-time stock, per-customer pricing and order push-back. It's the most sensitive B2B item and often justifies choosing custom.

How fast does it pay off? For a wholesaler with heavy order-desk load, entry savings amortise a custom portal in 9-14 months. The SaaS-vs-custom TCO crossover sits around 24-30 months.

Let's scope your project. Tell us your reseller volume, ERP and pricing rules and we'll price buy vs build with a costed 3-year TCO. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.