The verdict in three sentences
In 2026, a B2B e-commerce platform in London costs between 20,000 and 135,000 EUR (excl. VAT), depending on whether you handle simple customer accounts or multi-tier negotiated pricing with online quoting. The line item that blows up the budget is never the catalogue: it is the per-customer pricing rules, approval workflows and integration with your ERP. A properly scoped project ships in 10 to 20 weeks and pays for itself within the first year once volume exceeds 300 orders/month.
What a B2B platform costs in 2026
B2B is not B2C with different VAT. The structural functions (hierarchical accounts, negotiated prices, credit limits, quotes) radically change development effort. Here are the 2026 orders of magnitude seen in London.
| Tier | Scope | Price EUR (excl. VAT) | Timeline |
|---|---|---|---|
| Essential | Catalogue, customer accounts, group pricing | 20,000 - 35,000 | 8-10 wks |
| Growth | + online quotes, credit, multi-address | 38,000 - 70,000 | 12-16 wks |
| Custom | + CPQ, real-time ERP, approval workflows | 78,000 - 135,000 | 18-24 wks |
| Maintenance | Support, updates, hosting | 1,000 - 3,800/mo | recurring |
The jump between Growth and Custom comes 70% from bidirectional ERP integration and complex pricing rules (volume discounts, tiers, framework contracts).
What really drives the quote
Before comparing vendors, isolate the items that move the budget by more than 10,000 EUR. A spec that settles them halves the spread between quotes.
| Function | Estimated effort (person-days) | Cost EUR (excl. VAT) |
|---|---|---|
| Per-customer negotiated pricing | 8-15 | 6,800 - 13,000 |
| Online quotes + follow-ups | 6-12 | 5,100 - 10,200 |
| Real-time ERP integration | 12-25 | 10,200 - 21,000 |
| Hierarchical accounts (buyers/approvers) | 5-10 | 4,250 - 8,500 |
| Payment on terms / credit | 4-8 | 3,400 - 6,800 |
| Support portal & order history | 4-7 | 3,400 - 6,000 |
Average senior day rate in London in 2026: 850 EUR (excl. VAT)/day. A well-scoped offshore agency drops to 250-400 EUR/day at equivalent quality, hence invoice gaps of 40 to 60%.
Comparing the technical solutions
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| Solution | Entry cost EUR (excl. VAT) | Strength | B2B limit |
|---|---|---|---|
| Shopify Plus B2B | 28,000 - 55,000 | Fast, reliable | Limited pricing rules |
| Medusa (open-source) | 38,000 - 88,000 | Flexible, no licence | Needs senior dev |
| Custom Next.js | 66,000 - 135,000 | Total control | Longer timeline |
| BigCommerce B2B | 24,000 - 50,000 | Good value | Bounded customization |
For a catalogue under 5,000 SKUs with group pricing, Shopify Plus or BigCommerce are enough. Beyond that, or if your ERP dictates real-time prices, a Medusa or custom base avoids costly workarounds.
Mini case study
Claire, CFO of an industrial-supplies wholesaler in London (14M EUR revenue, 220 trade customers), receives 340 orders/month, 70% handled by phone and email. Each order takes 12 minutes of a sales rep, i.e. 68 hours/month at 34 EUR loaded, i.e. 2,312 EUR/month. By shifting 60% of orders to a B2B portal at 52,000 EUR (paid over 14 weeks), she saves 1,387 EUR/month in sales time, plus fewer data-entry errors. Payback in 32 months, before even counting the extra revenue from self-service, typically +8 to 15%.
FAQ
What is the minimum budget for a real B2B portal in London in 2026? Budget 20,000 EUR (excl. VAT) for a credible base with customer accounts and group pricing. Below that you get a disguised B2C site that will not withstand your pricing rules.
How long to go live? From 8 weeks for an essential tier to 24 weeks for custom with ERP integration. The bottleneck is almost always the readiness of your product and pricing data.
Must the ERP be integrated from day one? Not necessarily. A first phase with a daily CSV export costs 3,300 EUR versus 13,000 to 21,000 for real time; you switch to real time when volume justifies it.
Shopify Plus or custom? Shopify Plus if your pricing rules stay simple (fewer than 4 tiers) and your catalogue is under 5,000 SKUs. Custom beyond that, or if the self-service ROI exceeds 32,000 EUR/year.
What is the annual maintenance cost? Between 10 and 20% of the initial cost, i.e. 1,000 to 3,800 EUR (excl. VAT)/month depending on evolutions and SLA. This budget covers security, fixes and small enhancements.
Let's scope your project. Describe your catalogue, number of trade customers and ERP: we will define the right tier and indicative budget. 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.
