The verdict in three sentences
A complete B2B e-commerce platform in Montreal costs 60,000 to 160,000 EUR in full custom (headless architecture), versus 35,000 to 80,000 EUR on a composable SaaS foundation. B2B differs from B2C through the customer portal, per-account negotiated pricing and online quoting, which weigh the most. Think in 3-year TCO, not build cost: hosting, maintenance and evolutions often double the initial budget.
Budget line items of a B2B platform
On a 100,000 EUR project, the back-office and B2B pricing logic weigh as much as the front end.
| Line item | Share | EUR range |
|---|---|---|
| B2B catalog + negotiated pricing | 20 % | 12,000 - 32,000 |
| Customer portal + accounts | 18 % | 11,000 - 29,000 |
| Online quoting + approval | 15 % | 9,000 - 24,000 |
| Checkout + payment (card/transfer) | 14 % | 8,000 - 22,000 |
| Back-office & permissions | 15 % | 9,000 - 24,000 |
| ERP connection | 10 % | 6,000 - 16,000 |
| Design, testing, go-live | 8 % | 5,000 - 13,000 |
Timeline and team
A B2B project mobilizes 3 to 5 people over 4 to 8 months. Here is a typical 2026 plan with day rates of 500 to 800 EUR.
| Phase | Duration | Deliverables |
|---|---|---|
| Scoping & specs | 3 - 5 wks | Journeys, pricing rules, mockups |
| Foundation & catalog | 6 - 8 wks | B2B catalog, accounts, pricing |
| Quoting & checkout | 5 - 7 wks | Online quoting, payment, cart |
| ERP integration | 4 - 6 wks | Product/customer/order sync |
| UAT & go-live | 3 - 4 wks | Testing, training, go-live |
Composable SaaS or custom headless — 3-year TCO
Composable SaaS starts cheaper but its subscription accumulates; custom headless costs more to build but its TCO stabilizes.
| Line item (3 years) | Composable SaaS | Custom headless |
|---|---|---|
| Initial build | 35,000 - 80,000 EUR | 60,000 - 160,000 EUR |
| Platform subscription | 900 - 3,000 EUR/mo | 0 |
| EU hosting | partly included | 150 - 500 EUR/mo |
| Maintenance | 800 - 1,800 EUR/mo | 1,000 - 2,500 EUR/mo |
| 3-year TCO (order of magnitude) | 110,000 - 250,000 EUR | 110,000 - 270,000 EUR |
Mini case study
Sophie, head of a distribution mid-cap in Montreal, budgets a headless platform at 115,000 EUR delivered in 7 months, with 400 EUR/month hosting and 1,800 EUR/month maintenance. The customer portal and negotiated pricing remove 5 person-days/month of order entry, about 1,500 EUR/month in internal savings. Combined with a 12 % rise in average basket via online quoting, the platform yields an estimated payback of 24 months, TCO included.
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FAQ
Why does B2B cost more than B2C?
Because per-account negotiated pricing, the customer portal and online quoting make up more than half the budget. These blocks do not exist in standard B2C.
Composable SaaS or headless: which to choose?
Composable SaaS suits you if your rules are close to standard and you want to start fast. Headless wins as soon as your pricing, quoting workflows or ERP integrations are specific.
How long to go live?
Allow 4 to 8 months depending on scope, with ERP integration often the item that stretches the timeline.
What does maintenance cover?
Between 1,000 and 2,500 EUR/month: fixes, catalog evolutions, new payment methods, keeping the ERP connection alive and security.
Why think in 3-year TCO?
Because SaaS subscription and maintenance eventually exceed the build. Over 3 years the two options often converge, but headless leaves you code ownership.
Let's scope your project. Specify your catalog, negotiated-pricing rules and target ERP, and we will price the B2B platform (composable SaaS or headless) with a clear 3-year TCO. 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.