The verdict in three sentences
Integrating online payment in a B2B SME in Berlin costs 4,000 to 15,000 EUR in 2026 for the technical work, plus fees of 1.2 to 2.9% + a fixed amount per transaction depending on the PSP. The choice sits between Stripe, Mollie and Adyen, and above all on deferred payment (B2B BNPL) that secures your credit sales. Well integrated, collection speeds up and bad debt falls.
The integration cost in detail
Budget depends on the number of payment methods, accounting reconciliation and 3D Secure handling. Here is the typical breakdown.
| Item | 2026 range (EUR) | Comment |
|---|---|---|
| PSP integration (card + 3DS) | 2,000 - 6,000 | Stripe/Mollie/Adyen |
| Bank transfer + reconciliation | 1,000 - 4,000 | Auto matching |
| Deferred payment (B2B BNPL) | 1,500 - 5,000 | Scoring, limits |
| Invoicing + accounting | 1,000 - 4,000 | ERP/accounting export |
| Testing + PCI compliance | 500 - 2,000 | Tests, security |
| Total | 4,000 - 15,000 | 3-6 weeks |
PSP comparison 2026
Fees look similar but the cumulative gap on high volume is significant. Here are 2026 orders of magnitude for B2B.
| PSP | Card fees (Europe) | Transfer / SEPA | Strengths |
|---|---|---|---|
| Stripe | 1.5% + 0.25 EUR | 0.8% (capped) | Rich API, BNPL, docs |
| Mollie | 1.8% + 0.25 EUR | 0.25 EUR fixed | Simple, clear pricing |
| Adyen | 1.2% + 0.11 EUR | negotiable | High volume, global |
| Bank PSP | 2.0 - 2.9% + fixed | included | Bank relationship |
For an SME under 500,000 EUR annual flow, Mollie or Stripe are enough. Above 2M EUR, Adyen becomes attractive thanks to negotiable tiered fees.
Mini case study
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Nadia is CFO of a B2B wine merchant in Berlin, 3.4M EUR annual flow collected 60% by cheque and manual transfer. Average collection time is 48 days and bad debt is 1.8% of revenue, i.e. ~61,000 EUR/year.
She integrates Stripe with deferred payment at 11,000 EUR. Transaction fees rise to ~1.6% but collection time drops to 22 days and bad debt to 0.6%, saving ~41,000 EUR per year. Net of the extra fees, the annual gain exceeds 30,000 EUR: integration paid back in under six months.
FAQ
Which PSP for a B2B SME? Stripe or Mollie for simplicity and API under 2M EUR of flow; Adyen beyond that, to negotiate tiered fees. The decisive criterion is handling of deferred payment and reconciliation.
What do transaction fees really cost? Expect 1.2 to 2.9% + a fixed amount per card payment in 2026. On 3M EUR of flow at 1.6%, that is ~48,000 EUR/year: a line to negotiate as volume grows.
Is deferred payment risky? With B2B BNPL, the provider often takes the default risk for a commission. You are paid immediately while the customer settles at 30/45/60 days.
Do we need PCI-DSS compliance? Yes, but by using a PSP that hosts card data (secure fields), your SME stays in the lightest scope. The integration avoids storing card numbers.
How long to integrate everything? Between 3 and 6 weeks for card, transfer, 3DS and reconciliation. Deferred payment adds one to two weeks to configure scoring and limits.
Let's scope your project. Tell us your transaction volume, current payment methods and collection time: we scope the integration and a budget of 4,000 to 15,000 EUR. 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.
