The verdict in three sentences
Below 300,000 EUR of online revenue per year, a B2B SaaS license (Shopify Plus, BigCommerce) is the rational choice: fast launch, predictable cost, low commission. Above that, once your pricing rules, ERP connectors and volumes get heavy, a custom headless build between 45,000 and 120,000 EUR wins over three years. The real trade-off is not the entry price but TCO: license + commission + maintenance + hosting.
SaaS license vs custom: the 3-year cost
A license bills every month whatever your usage, sometimes plus a revenue commission. Custom requires a heavy upfront investment, then annual maintenance of 12 to 18 % of the build cost and EU hosting of 150 to 600 EUR/month.
| Item (2026 order of magnitude) | Shopify Plus B2B | BigCommerce B2B | Custom headless |
|---|---|---|---|
| Monthly license | ~2,300 EUR | ~1,800 EUR | 0 EUR |
| Platform commission | 0.15 % of revenue | 0 % | 0 % |
| Initial build | 8,000 - 25,000 EUR (theme + integ.) | 8,000 - 25,000 EUR | 45,000 - 120,000 EUR |
| Annual maintenance | included (updates) | included | 12 - 18 % of build |
| Hosting | included | included | 150 - 600 EUR/mo |
| Total 3 years (1 M EUR revenue) | ~110,000 EUR | ~90,000 EUR | ~95,000 - 165,000 EUR |
Reading: at 1 M EUR of online revenue, the 0.15 % commission is 18,000 EUR over three years on Shopify Plus, on top of the license. Custom becomes competitive as revenue grows or when functional needs exceed the standard scope.
TCO by revenue tier
The higher your revenue, the more commission and license limits weigh. The table below compares the all-in annual total cost of ownership.
| Annual e-commerce revenue | SaaS license + commission | Custom (build amortized 4 yrs + maintenance) |
|---|---|---|
| 200,000 EUR | ~28,000 EUR/yr | ~32,000 EUR/yr |
| 500,000 EUR | ~29,000 EUR/yr | ~33,000 EUR/yr |
| 1,000,000 EUR | ~34,000 EUR/yr | ~35,000 EUR/yr |
| 3,000,000 EUR | ~48,000 EUR/yr | ~38,000 EUR/yr |
| 6,000,000 EUR | ~66,000 EUR/yr | ~42,000 EUR/yr |
The tipping point sits around 1.5 to 2 M EUR of revenue: below it SaaS wins on simplicity; above it custom saves the commission and removes premium platform fees.
The B2B functions that justify the budget
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B2B e-commerce is not B2C with a "pro" button. These functions are either native or must be built.
| B2B function | Standard SaaS | Custom |
|---|---|---|
| Per-client / negotiated pricing | Partial (Plus) | Full, no limit |
| Online quotes (quote-to-order) | Paid add-on | Native |
| Net-30 / net-60 payment | Rare | Custom |
| Credit limit per account | No | Yes |
| ERP connector (Sage, SAP B1, Odoo) | Via app 8,000 - 25,000 EUR | Built-in |
| CSV order / fast reorder | Add-on | Native |
| Multiple users per client account | Limited | Unlimited |
Mini case study
David, sales director of an industrial-supplies distributor in Toronto, does 2.4 M EUR of revenue and wants to move 40 % online. On Shopify Plus, the 0.15 % commission on ~960,000 EUR online revenue is 1,440 EUR/yr, plus 27,600 EUR license, i.e. ~29,000 EUR/yr, before quote and net-30 add-ons (~6,000 EUR/yr). Total: ~35,000 EUR/yr. A custom build at 85,000 EUR amortized over 4 years (21,250 EUR/yr) plus 15 % maintenance (12,750 EUR) plus hosting (4,800 EUR) comes to ~39,000 EUR the first year, then ~30,000 EUR, with all functions included. Over 4 years, custom saves him ~20,000 EUR while removing his commission dependency.
FAQ
What is the minimum budget to start in B2B e-commerce? Budget 8,000 to 25,000 EUR for a SaaS launch with theme and basic integrations, or 45,000 EUR minimum for a first custom foundation. Below that, you have an online catalog, not a real B2B platform.
Is headless commerce worth the premium? Headless splits the front (fast, custom) from the back (commerce, ERP). It costs 20 to 40 % more to build but enables ultra-optimized funnels and higher conversion: worth it above ~1 M EUR revenue.
How much is annual maintenance on a custom build? Maintenance is 12 to 18 % of the build cost, i.e. 6,000 to 22,000 EUR/yr for a 45,000 to 120,000 EUR project. It covers security, evolutions and fixes.
Can you migrate later from SaaS to custom? Yes, and it is common: start on SaaS to validate the market, then move to a custom foundation once revenue and needs stabilize. Plan 3 to 5 months for the migration project.
How long to deliver a custom platform? A working MVP ships in 3 to 4 months, a full platform with ERP connector and net-30 in 5 to 8 months depending on scope.
Let's scope your project. Tell us your target e-commerce revenue, your B2B payment methods and your ERP: we will cost SaaS vs custom over 3 years. 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.
