The verdict in three sentences
For 95% of SMEs, integrating a standard PSP is the right call: low entry cost, compliance delegated, fast go-live. A custom payment build is only justified above ~3-5M EUR of annual volume, when PSP arbitrage and flow control earn more than the compliance burden costs. This is not a technical question, it's a 3-year TCO question.
Two models, two cost structures
The off-the-shelf PSP shifts complexity (and PCI-DSS compliance) to the provider. Custom hands you control, but transfers the regulatory burden.
| Item | Off-the-shelf PSP | Custom payment build |
|---|---|---|
| Initial integration | 6,000 to 18,000 EUR | 40,000 to 90,000 EUR |
| PCI-DSS compliance / year | Included (delegated) | 8,000 to 20,000 EUR/year |
| Transaction fees | Full PSP rate | Negotiated / interchange++ |
| Go-live time | 2 to 5 weeks | 4 to 9 months |
| Maintenance / year | 2,000 to 6,000 EUR | 15,000 to 40,000 EUR |
| Flow control | Limited | Full (routing, retry) |
Custom does not remove PSP fees: it gives you the leverage to negotiate them and route payments, which only has value at high volume.
3-year TCO: the real comparison
Estimate (2026 order of magnitude) integration + compliance + maintenance, excluding transaction fees, for a European e-commerce store.
| Annual volume | Off-the-shelf PSP (3-yr TCO) | Custom (3-yr TCO) | Verdict |
|---|---|---|---|
| 500,000 EUR | ~24,000 EUR | ~120,000 EUR | PSP clearly |
| 1,500,000 EUR | ~30,000 EUR | ~135,000 EUR | PSP |
| 3,000,000 EUR | ~38,000 EUR | ~145,000 EUR | Tipping zone |
| 6,000,000 EUR | ~50,000 EUR | ~160,000 EUR | Custom worth considering |
| 12,000,000 EUR | ~70,000 EUR | ~180,000 EUR | Custom pays off |
Above 6M EUR, saving 0.2-0.4% of transaction fees (via negotiation and routing) exceeds the custom premium: on 12M EUR, 0.3% = 36,000 EUR/year recovered.
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Mini case study
Mathieu, CIO of a B2B distribution SME in Amsterdam, processes 4M EUR/year and is hesitating. His PSP costs ~2.3% all-in, i.e. ~92,000 EUR/year in fees. A custom orchestration layer (65,000 EUR + 14,000 EUR/year compliance) lets him negotiate to ~2.0% and route traffic: saving of ~12,000 EUR/year in fees + 1.5 acceptance points (~60,000 EUR of revenue saved). Return on investment in ~18 months, provided volume stays stable or grows.
FAQ
Does custom make me the owner of the payment data? You keep control of the flows and routing logic, but card data storage stays subject to PCI-DSS — hence the irreducible annual compliance cost.
Can we do a hybrid mix? Yes: keep a PSP for the acquirer and add a thin in-house orchestration layer. It's often the best control/cost ratio between 3 and 6M EUR of volume.
How long for a custom project? Budget 4 to 9 months depending on scope (tokenisation, 3-D Secure, reconciliation, failover). A standard PSP plugs in within 2 to 5 weeks.
What costs the most long term? PCI-DSS compliance and security maintenance: 8,000 to 20,000 EUR/year recurring, often underestimated in in-house projects.
When should you NOT go custom? Below 3M EUR of volume, almost always. The fee saving never covers 40,000-90,000 EUR of integration plus compliance.
Let's scope your project. Tell us your annual volume and current PSP fees: we compute your 3-year TCO and tipping point (PSP integration 6,000-18,000 EUR, custom orchestration on quote). 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.
