The verdict in three sentences
A custom B2B e-commerce platform makes sense as soon as your commercial rules (negotiated per-account pricing, credit lines, minimum order quantities, ERP-driven reordering) outgrow standard solutions. Budget 40,000 to 150,000 EUR as a one-off build, versus 2,000 to 10,000 EUR/month for a rented SaaS platform. The tipping point depends on your order volume and the weight of your B2B specifics: beyond ~300 active pro accounts, custom often becomes the rational choice.
Custom vs off-the-shelf: real 2026 cost
Rented solutions add up fast: subscription, volume commission, paid apps and integrations. Custom concentrates cost upfront, then stabilises into maintenance. Here are 2026 orders of magnitude for a manufacturer selling to professional buyers.
| Item | Custom | Shopify Plus (B2B) | BigCommerce B2B |
|---|---|---|---|
| Initial setup / build | 40,000 - 150,000 EUR | 3,000 - 15,000 EUR (integrator) | 4,000 - 20,000 EUR |
| Monthly subscription | Hosting 150 - 800 EUR | ~2,300 EUR/month | ~1,800 - 3,500 EUR/month |
| Platform commission | 0% | 0.15 - 2% by gateway | 0% (gateway fees) |
| Apps / modules | Included in build | 200 - 900 EUR/month combined | 150 - 700 EUR/month |
| Annual maintenance | 15 - 20% of build | Included | Included |
| Code ownership | Full | No (lock-in) | No (lock-in) |
What drives up the B2B bill
The core of the price isn't product pages: it's business rules. Each block below adds developer-days.
| B2B feature | Complexity | Range (EUR) |
|---|---|---|
| Per-account / negotiated price lists | High | 8,000 - 25,000 |
| Credit lines and terms-based payment | High | 6,000 - 18,000 |
| Fast reorder / order by SKU | Medium | 4,000 - 12,000 |
| ERP integration (SAP, Sage, Cegid) | Very high | 12,000 - 40,000 |
| Online quotes + multi-level approval | Medium | 5,000 - 15,000 |
| Multi-user accounts per customer | Medium | 4,000 - 10,000 |
Mini case study
Mark, MD of an industrial components SME in London, turns over 4.2M EUR, 60% from 220 recurring pro accounts. His sales reps spend 30% of their time keying in orders received by email. A custom portal at 85,000 EUR (per-account pricing + credit + Sage connector) automates 70% of recurring orders. Estimated gain: 1.2 sales FTE redeployed (~48,000 EUR/year) and +6% basket via suggested reorders. Payback in ~16 months, with proprietary code as a bonus.
FAQ
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How long to deliver a custom B2B platform?
Expect 3 to 6 months for a standard scope (catalogue, accounts, pricing, one ERP connector). Projects with multiple integrations or data migration often exceed 8 months.
Is custom always more expensive than Shopify Plus?
Not over 3 years. A rented solution at 2,300 EUR/month + apps + commissions easily reaches 100,000 - 130,000 EUR combined, with no code ownership. Custom becomes competitive beyond a certain volume.
Can we start small then extend?
Yes. A first version at 40,000 - 55,000 EUR covers catalogue, accounts and pricing, then you add credit and ERP in batches. This is often the healthiest path.
What maintenance budget should we plan?
Maintenance of 15 to 20% of the build cost per year covers fixes, minor evolutions and security, i.e. 6,000 to 30,000 EUR/year depending on the project.
Do we need an ERP in place before launching?
Not necessarily, but ERP integration is the item that delivers the most ROI (real-time stock, reordering, invoicing). Plan for it at design time even if you activate it in phase 2.
Let's scope your project. Tell us about your catalogue, your number of pro accounts and your ERP: we'll scope a costed perimeter (build + maintenance) matched to your 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.
