The verdict in three sentences
A custom B2B e-commerce platform in London runs between 45,000 and 120,000 EUR in 2026, depending on catalogue complexity, price lists and ERP integration. A B2B SaaS (200 to 2,000 EUR/month) launches faster but hits a ceiling as soon as you have negotiated per-customer prices, credit terms and approval workflows. The decision is settled not on the licence price, but on the cost of processing an order that the portal removes.
What a B2B ordering portal covers
A sales director doesn't want a consumer shop: they want their trade customers to find their negotiated prices, their history, their credit limits and a 3-click reorder. The key building blocks of a 2026 B2B project:
- Customer accounts with multiple buyers per company and permission tiers.
- Per-customer or per-group pricing (price lists, volume discounts, net prices).
- Credit and deferred payment (30/60 days), quote-to-order, budget per buyer.
- ERP integration (Sage, SAP Business One, Cegid) for real-time stock, prices and orders.
- Fast reordering: favourite lists, CSV import, order by SKU.
| Item | B2B SaaS | Custom London (2026) |
|---|---|---|
| Entry cost | 0-5,000 EUR setup | 45,000-120,000 EUR |
| Subscription | 200-2,000 EUR/month | Hosting 150-600 EUR/month |
| Per-customer pricing | Often limited | Unlimited, bespoke |
| ERP integration | Limited connectors | Custom, real-time |
| UX customisation | Templates | Full |
| Time to launch | 4-10 weeks | 4-8 months |
| Code ownership | No | Yes |
Build vs buy: the real math
SaaS wins on time-to-market and upfront cash; custom wins as soon as order volume and the specificity of your price lists explode. Here is the 2026 order of magnitude over 3 years for a catalogue of 8,000 SKUs and 300 trade customers.
| Scenario | Upfront cost | 3-year recurring | 3-year total |
|---|---|---|---|
| Mid-range B2B SaaS | 3,000 EUR | 1,200 EUR/mo = 43,200 EUR | 46,200 EUR |
| High-end B2B SaaS | 8,000 EUR | 2,000 EUR/mo = 72,000 EUR | 80,000 EUR |
| Custom (dedicated portal) | 75,000 EUR | 400 EUR/mo = 14,400 EUR | 89,400 EUR |
At constant volume, custom costs more over 3 years, but it captures the value: every order placed online instead of by phone saves sales time. That's where the ROI flips.
Mini case study
James, sales director of an industrial-supplies distributor in London, processes 1,400 orders/month. Each order taken by phone or email ties up on average 12 minutes of an inside-sales rep (loaded cost ~28 EUR/h). That's a processing cost of ~6.60 EUR/order, or 9,240 EUR/month.
After deploying a portal at 78,000 EUR, 60% of orders move to self-service. Monthly saving: 1,400 x 0.60 x 6.60 = 5,544 EUR/month, or 66,528 EUR/year. The portal pays for itself in ~15 months, before counting reorder gains and fewer data-entry errors.
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FAQ
What does a custom B2B portal really cost in London in 2026?
Expect 45,000 to 120,000 EUR depending on catalogue, price lists and ERP. A median project lands around 70,000-85,000 EUR.
What timeline should I plan?
Between 4 and 8 months: 3-4 weeks of scoping, 3-5 months of development, 1 month of testing and data migration.
Isn't a B2B SaaS enough?
It's enough while your pricing is simple. As soon as you manage net prices per customer, credit terms and an in-house ERP, SaaS connectors buckle and total cost climbs past 2,000 EUR/month.
Can we integrate our existing ERP?
Yes: Sage, SAP Business One or Cegid integrate via API or middleware. Budget 8,000 to 20,000 EUR for this line in the overall project.
How do I measure ROI?
Track the cost per order processed before/after and the self-service order rate. Moving from 0 to 60% self-service often pays back in 12 to 18 months.
Let's scope your project. Share your catalogue, price lists and ERP, and we'll price a B2B portal matched to your order volume. 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.
