The verdict in three sentences
For a service SME in London, an online payment integration costs between GBP 3,500 and 13,000 in 2026, depending on how much you automate (deposits, subscriptions, dunning). The real decision is not the build price but hosted checkout vs custom integration, which sets your PCI DSS exposure. Expect 3 to 6 weeks and transaction fees of 1.4-2.9% + 20p that weigh far more over 12 months than the upfront quote.
What you actually pay for
Costs split into three blocks: technical integration, per-transaction fees, and maintenance. A service SME typically collects project deposits and recurring retainers (support, managed services); it is the recurring revenue that justifies automation.
| Item | Hosted page (Stripe Checkout) | Custom integration (API) |
|---|---|---|
| Initial build | GBP 3,500 - 6,000 | GBP 8,000 - 13,000 |
| Timeline | 3 - 4 weeks | 5 - 6 weeks |
| PCI DSS scope | SAQ A (minimal) | SAQ A-EP / D (heavy) |
| Recurring (Bacs + card) | included | included |
| 3D Secure 2 (SCA) | handled by provider | to implement |
| Monthly support | GBP 130 - 260/mo | GBP 260 - 520/mo |
A hosted page shifts PCI burden to Stripe or GoCardless: for 90% of service SMEs, that is the right call. Custom builds only pay off when checkout must stay 100% inside your own interface (SaaS, client portal).
Transaction fees: the invisible cost
| Payment method | 2026 fee (ballpark) | Use case |
|---|---|---|
| UK/EU card | 1.4% + 20p | One-off deposit |
| Non-EU / premium card | 2.9% + 20p | International clients |
| Bacs Direct Debit | 1% capped ~GBP 2 | Monthly retainer |
| Wallet (Apple/Google Pay) | 1.4% + 20p | Mobile |
| Refund | fixed fees not returned | Dispute |
For a recurring retainer, Bacs Direct Debit is far cheaper than card above roughly GBP 30 per invoice. A client on GBP 400/month costs about GBP 2 via Bacs versus GBP 5.80 on card. Across 200 subscribers, the annual gap tops GBP 9,000.
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Mini case study
Sarah runs an IT services SME in London, 18 staff. She collects 40 deposits/month (avg GBP 1,500) and 90 support retainers (avg GBP 350/month). Chosen build: hosted Stripe Checkout + GoCardless Bacs, GBP 5,400, live in 4 weeks. Monthly fees: deposits 40 x (1,500 x 1.4% + 0.20) = GBP 848; retainers on Bacs 90 x ~GBP 2 = GBP 180. By moving retainers from card to Bacs she saves roughly GBP 5,000/year. The project pays for itself in under 11 months on fee savings alone.
FAQ
Do I have to be PCI DSS certified myself? With a hosted page (Stripe Checkout, GoCardless), you fall under the lightest questionnaire, SAQ A: your servers never touch card numbers. A full API integration can require SAQ D, far costlier to maintain.
How long to start taking payments online? Roughly 3 to 4 weeks for a hosted page, 5 to 6 weeks for a custom build with subscriptions and automated dunning.
Bacs or card for subscriptions? Bacs Direct Debit (capped ~GBP 2) beats card above GBP 30 per invoice, but its initial failure rate is higher, so plan a retry/dunning policy.
What is the annual maintenance budget? Between GBP 1,600 and 6,200/year of support depending on complexity, excluding transaction fees. Budget also for ongoing 3D Secure and SCA rule updates.
Can I keep my current website? Yes, the integration bolts onto your existing site (WordPress, Next.js, custom) via redirect or widget, with no full rebuild in most cases.
Let's scope your project. Share your monthly deposit and subscription volumes, your current stack and your deadline; we will frame hosted vs custom with an indicative budget. 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.
