How Much Does a B2B Marketplace Cost to Build in 2026

The verdict in three sentences

A B2B marketplace isn't e-commerce with several vendors: it's a financial system (payment split, commissions, payouts) and a trust system (KYC, moderation, disputes). A SaaS marketplace (Mirakl, Sharetribe, 99-999 EUR/month) speeds up the MVP; custom (60,000-180,000 EUR) becomes profitable beyond a significant GMV and for a specific commission model. The golden rule: automated payment split is not optional.

The blocks that make (or break) a marketplace

A marketplace lives or dies on its back office. Here are the essential blocks and their weight in the development budget.

Payment split (automatically dividing an order between vendor and platform) is the most critical and most underestimated item. An error here means underpaid vendors and a platform that loses trust.

SaaS vs custom: the numbers

As a 2026 order of magnitude, SaaS wins to validate an idea and reach the first vendors. Once GMV climbs, the percentage the SaaS takes exceeds the amortized cost of custom: that's the economic tipping point.

Mini case study

Fatou, heading a trade federation launching a B2B supplies marketplace among members, targets 1.5M EUR GMV in year one, at an 8% commission, i.e. 120,000 EUR of platform revenue.

With a SaaS taking the equivalent of 2.5% of GMV (fees + transaction), annual cost reaches ~37,500 EUR. A custom build at 95,000 EUR + 15%/yr maintenance (14,250 EUR) costs 109,250 EUR in year one, then 14,250 EUR/year. From year 2, custom saves ~23,000 EUR/year, and a projected 3M EUR GMV widens the gap further. SaaS stays relevant only to test appetite before investing.

FAQ

What platform commission should you target in B2B? The standard runs 5-20% depending on sector and added value. In B2B supplies, 5-10% is common; for services, 10-20%. The split must be automated whatever the rate.

What does a custom marketplace really cost in 2026? From 60,000 to 180,000 EUR depending on the blocks (KYC, disputes, multi-country payouts). Add 12-20%/yr maintenance for upkeep and evolution.

Is SaaS a trap? Not to start: Sharetribe or Mirakl validate the concept fast. The trap is staying on it at high GMV, where the percentage taken exceeds the cost of amortized custom.

Is payment split really mandatory? Yes. Without automatic buyer→vendor/platform allocation and scheduled payouts, you handle disbursements by hand: untenable and legally risky beyond a few dozen vendors.

When do you reach the tipping point to custom? Usually once annual SaaS fees (often a % of GMV) exceed the maintenance of amortized custom — frequently between 1 and 2M EUR GMV.

Let's scope your project. Give us your target GMV, commission rate and KYC/payout needs (single or multi-country), and we'll steer you to SaaS for the MVP or custom, with an indicative budget. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.