The verdict in three sentences
A consumer store manages a catalogue and a cart; a B2B platform manages customer accounts, negotiated pricing, credit limits and approval workflows. For a London wholesaler or manufacturer selling to trade, a packaged solution (Shopify B2B, BigCommerce) launches fast but hits the wall of your business rules; a custom build costs £40k-£95k and pays back through a lower cost per order. The real ROI is not the design: it is self-service freeing your sales team from routine reorders.
Packaged or custom: what does a B2B budget really cover?
SaaS B2B platforms charge subscription, modules and often a transaction cut; custom is a one-off investment plus hosting. 2026 order of magnitude for the London market:
| Line item | Shopify B2B / BigCommerce | Custom (Next.js + API) |
|---|---|---|
| Initial setup | £7,000 - £18,000 | £40,000 - £95,000 |
| Platform subscription | £2,000 - £3,600 / yr | £0 (hosting £1,000 - £3,200 / yr) |
| Third-party apps / modules | £2,600 - £8,000 / yr | included in build |
| Account-level pricing | Native (high tier) | Custom, unlimited |
| Approval workflow | Limited / third-party app | Custom |
| Net terms (net 30) | Workaround | Native |
| 3-year TCO (est.) | £40,000 - £70,000 | £50,000 - £105,000 |
Over 3 years the gap narrows: SaaS looks cheaper up front, but subscription, apps and transaction cuts catch up with custom as soon as volume and business rules grow.
The B2B features that justify custom
It is the B2B specifics, missing or throttled in SaaS, that tip the decision:
| B2B feature | Operational impact | Build complexity |
|---|---|---|
| Account-specific catalogue | Each customer sees their products and prices | Medium |
| Volume price tiers | Automatic step discounts | Medium |
| Quick order (SKU + quantity) | Reorder in < 2 min | Low |
| Credit limit and outstanding balance | Auto-block on overrun | High |
| Multi-level approval workflow | Buyer → approver → order | High |
| Online quote convertible to order | Shorter sales cycle | Medium |
| Punchout / customer ERP connection | Enterprise procurement integration | High |
Budget 4 to 7 months of development for a Growth scope, including project management and ERP integration.
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Mini case study
Thibault runs the sales division of an industrial-supplies wholesaler in London: 900 trade customers, 12,000 SKUs, 220 orders a day of which 60 % are plain reorders. His 6 reps spent 3 hours a day re-keying orders received by email or phone, an estimated processing cost of £8 per order. He invests £58,000 in a custom platform with quick order, account pricing and credit limits. Result: 55 % of orders move to self-service, processing cost drops to £4.80 (-40 %) and the reps recover the equivalent of 2 FTE for prospecting. Estimated annual saving: £100,000 — payback in under 8 months.
FAQ
Is Shopify B2B enough to start? Yes for a simple catalogue and a few accounts with negotiated pricing: it is fast and reliable. It shows its limits on approval workflows, managed credit limits and deep ERP integration, where app workarounds get costly (£2,600-£8,000 / yr).
How long for a custom platform? Budget 4 to 7 months depending on scope: 4 months for a catalogue + accounts + quick-order core, 7 months with approval workflow, credit limits and real-time ERP sync.
Can the platform connect to my ERP or accounting software? Yes, it is the core of a B2B project: stock, price and customer sync via API or EDI. Budget £7,000-£18,000 depending on how open your ERP is (Sage, SAP Business One, NetSuite, Microsoft Dynamics).
Can net terms be handled online? Yes: the platform applies the account credit limit, releases the order within the ceiling and issues the invoice at term (net 30/60). Immediate payments (card, transfer) stay available for new customers.
What volume justifies custom over SaaS? As an order of magnitude, above £130,000 of online orders per year or with strong business rules (approval, credit limits, punchout), custom becomes more cost-effective over 3 years than a stack of subscriptions and apps.
Let's scope your project. Tell us about your catalogue, your number of trade accounts and your pricing rules, and we will scope a Starter, Growth or custom build with an indicative budget and timeline. 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.
