The verdict in three sentences
Bringing online payments in-house splits into two distinct budgets: the project (Stripe/PSP integration + webhooks + 3-D Secure, 6,000 to 14,000 EUR) and the recurring (PSP fees of 1.4 to 2.9 % + 0.25 EUR/transaction). The real gain comes from the automatic accounting reconciliation module (8,000 to 16,000 EUR) that removes 5 to 15 days/month of manual matching. For a CFO, it's a project investment repaid in finance-team time, not in revenue.
Project cost vs recurring fees
Don't confuse one-off development with transaction fees: they are two budget lines that don't obey the same logic.
| Item | Nature | 2026 amount |
|---|---|---|
| Stripe/PSP integration + webhooks + 3-D Secure | Project (one-off) | 6,000 - 14,000 EUR |
| Automatic reconciliation module | Project (one-off) | 8,000 - 16,000 EUR |
| PSP fee per transaction | Recurring | 1.4 - 2.9 % + 0.25 EUR |
| Maintenance / monitoring | Recurring | 300 - 900 EUR/month |
The reconciliation module automatically matches payments, invoices and payouts: it's what turns a simple payment button into a reliable, auditable accounting chain.
PSP fee matrix by volume
PSP fees are negotiable above a certain volume. Here are 2026 orders of magnitude for an 80 EUR average basket.
| Monthly volume | Average fee | Estimated monthly cost (EUR) | Negotiation leverage |
|---|---|---|---|
| 500 transactions | 2.9 % + 0.25 | ~1,285 | Low |
| 2,000 transactions | 2.4 % + 0.25 | ~4,340 | Medium |
| 5,000 transactions | 1.9 % + 0.25 | ~8,850 | High |
| 15,000 transactions | 1.4 % + 0.25 | ~20,550 | Negotiable (dedicated contract) |
At high volume, a 0.3-point fee cut means thousands of euros a month: the PSP can be renegotiated, and a solid reconciliation module makes multi-PSP management easier.
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Mini case study
Elodie, CFO of an online-retail SMB in London, ties up 1.5 FTE in accounting on payment/invoice matching, about 10 days/month. Loaded cost: about 3,200 EUR/month. An automatic reconciliation module at 12,000 EUR brings this work down to ~2 days/month, saving ~2,560 EUR/month, 30,700 EUR/year. ROI is reached in about 5 months, and the finance team refocuses on control rather than data entry.
FAQ
Why separate project cost from PSP fees? Because the project is an amortisable investment, while PSP fees are a variable charge proportional to revenue. Mixing them distorts profitability analysis.
Is automatic reconciliation worth its cost? Yes as soon as manual matching exceeds 5 days/month: at 8,000-16,000 EUR, it typically repays in 4 to 8 months in accounting time saved.
Can Stripe/PSP fees be negotiated? Yes from a few thousand transactions/month: a dedicated contract or Interchange++ can cut the effective rate by 0.2 to 0.6 points.
Is 3-D Secure mandatory? Yes, PSD2 mandates strong authentication (SCA) in Europe. A good integration handles exemptions to limit friction without losing compliance.
Can several PSPs be connected? Yes, and it's recommended at high volume: route payments to the cheapest or best-performing PSP per country. The reconciliation module must then consolidate several sources.
Let's scope your project. Give us your transaction volume, average basket and accounting tool: we cost the PSP integration and reconciliation module with ROI in days saved. 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.