The verdict in three sentences
A multi-vendor B2B marketplace costs between 60,000 and 180,000 EUR (excl. tax) in 2026, depending on vendor count, payment-split complexity and the level of KYC required. The realistic timeline is 24 to 36 weeks, but an MVP focused on a single category ships in 12-16 weeks to validate the market before the full investment. The most underestimated line item is not development but GMV profitability: without transaction volume, a 10% commission never covers maintenance.
What a B2B marketplace really costs
A marketplace is not an e-commerce site with several seller accounts. It adds three heavy building blocks: vendor management (onboarding, KYC, delegated catalog), payment splitting (automatic buyer / vendor / platform distribution) and governance (moderation, disputes, payouts). Each one raises the bill.
| Item | 2026 range (EUR excl. tax) | Indicative timeline |
|---|---|---|
| Scoping & functional specs | 6,000 - 12,000 | 3-4 weeks |
| Vendor area (onboarding, catalog) | 12,000 - 30,000 | 5-8 weeks |
| Payment split + payouts | 10,000 - 25,000 | 4-6 weeks |
| KYC / vendor verification | 5,000 - 15,000 | 2-4 weeks |
| Platform back office (commissions, disputes) | 12,000 - 35,000 | 5-8 weeks |
| B2B buyer front (accounts, pricing, quotes) | 10,000 - 40,000 | 5-9 weeks |
| QA, security, go-live | 5,000 - 23,000 | 3-5 weeks |
| Full project total | 60,000 - 180,000 | 24-36 weeks |
On top of this comes maintenance (evolutive) at 15%/year of the initial cost, i.e. 9,000 to 27,000 EUR excl. tax per year, plus payment-provider fees (0.25 to 1.4% per transaction depending on the PSP and split).
The commission model decides everything
The commission rate directly sets your break-even. In B2B, baskets are large but vendor margins thinner than in B2C: too high a rate scares vendors away, too low a rate fails to fund the platform.
| Model | 2026 rate | Suited to |
|---|---|---|
| Per-transaction commission | 5 - 20% of GMV | High-rotation categories |
| Vendor subscription | 49 - 499 EUR/month | Recurring vendors |
| Mixed (subscription + reduced commission) | 99 EUR + 3-8% | Most stable model |
| Promotion / placement fees | 200 - 2,000 EUR/campaign | Additional monetization |
| Lead / matchmaking | 15 - 150 EUR/lead | Services marketplace |
A mixed model (subscription plus reduced commission) smooths revenue and cuts dependence on volume, which reassures when GMV ramps up slowly.
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Mini case study
Stephane, founder of a B2B industrial-supplies marketplace in Lille, invests 95,000 EUR excl. tax in a 24-week MVP, with an 8% commission on GMV. His annual maintenance is 14,250 EUR excl. tax and fixed costs (hosting, PSP, support) run at 1,500 EUR/month, i.e. 18,000 EUR/year. His recurring charges therefore reach 32,250 EUR/year. To cover them at 8% commission, he needs an annual GMV of 403,000 EUR (around 33,600 EUR/month in transactions). At an average basket of 850 EUR, that is 40 orders/month: achievable from 15 active vendors. The initial development amortizes at roughly 1.6M EUR of cumulative GMV.
FAQ
Should I build custom or use a SaaS solution? A marketplace SaaS (like Mirakl or Sharetribe) starts at 500-2,500 EUR/month but limits B2B customization (per-customer pricing, quotes, multi-buyer accounts). Custom costs more upfront but pays off once the business logic is specific, typically beyond 200,000 EUR of annual GMV.
How long for a first MVP? Plan 12 to 16 weeks for a single-category marketplace with payment splitting and a minimal back office. That is the ideal window to validate vendor buy-in before committing the full 60,000 EUR-plus budget.
Is payment splitting mandatory? Yes, as soon as you collect on behalf of vendors. In Europe this often requires payment-agent status or an approved marketplace PSP (Stripe Connect, Mangopay, Lemonway), with fees of 0.25 to 1.4% per transaction.
What is the real financial risk? Under-population: a technically perfect platform with no vendors and no GMV. That is why the GMV break-even must be calculated before the first line of code, and the MVP designed to recruit the first 10-20 vendors.
Is 15%/year maintenance negotiable? Yes, depending on scope: a corrective-only contract runs around 8-10%, while 15-20% covers regular functional evolution. For a growing marketplace, high maintenance is an investment, not a sunk cost.
Let's scope your project. Tell us your target category, your vendor count and your commission model, and we will scope the MVP then the full roadmap. 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.
