Choosing a payment gateway is one of the most consequential decisions a UK business makes. It affects transaction costs, customer experience, integration complexity, and how easily you can expand to new channels and markets.
This guide compares the best payment gateways available in the UK, covering fees, features, integration options, and which gateway suits which business type.
What Is a Payment Gateway?
A payment gateway is the technology that authorises card transactions. When a customer enters their card details — on a website, in an app, over the phone, or at a terminal — the gateway communicates with the card network and the customer's bank to approve or decline the payment.
Most modern payment gateways also function as acquirers and payment processors, meaning they handle the full transaction lifecycle: authorisation, settlement, and reporting.
Best UK Payment Gateways Compared
Gateway | Best For | UK Card Fees | Key Strength | Integration |
|---|---|---|---|---|
Stripe | Online businesses, SaaS | 1.4% + 20p | Developer experience, documentation | API, SDKs, plugins |
Adyen | Enterprise, multi-region | IC + 0.10-0.25€ | Global acquiring, unified commerce | API, drop-in components |
Worldpay | High-volume retail | From 0.75% + 10p | UK market penetration, terminal range | API, hosted page, POS |
Checkout.com | High-growth online | IC + ~0.20% | Approval rates, performance | API, hosted page, SDKs |
Square | Small business, retail | 1.75% (in-person) | POS + online in one | POS hardware, API, plugins |
GoCardless | Direct Debit / recurring | 1-2% + 20p | Bank-to-bank payments | API, dashboard, plugins |
PayPal | Consumer payments | 2.9% + 30p | Customer trust, wallet ubiquity | Buttons, API, plugins |
Mollie | European e-commerce | 1.2% + 25p | European payment methods, simplicity | API, plugins |
Stripe
Stripe is the default choice for developer-led businesses. Its API documentation is the industry standard, its SDKs cover every major language and framework, and its product surface extends well beyond basic payments into billing, subscriptions, fraud detection (Radar), and financial infrastructure.
Fees: 1.4% + 20p for UK cards. 2.5% + 20p for international cards. No monthly fee.
Best for: Online businesses, SaaS platforms, startups, developer-first teams.
Limitation: Flat-rate pricing is expensive at high volumes. For businesses processing over £100K/month, interchange-plus from Adyen or Checkout.com is typically cheaper. Stripe Connect for platforms locks you into Stripe's ecosystem.
Adyen
Adyen is the gateway of choice for enterprise and multi-region businesses. It operates as a full-stack acquirer in 30+ countries, meaning it processes transactions locally — reducing cross-border interchange costs and improving approval rates.
Fees: Interchange + €0.10-0.25 per transaction. No monthly fee but a €120/month minimum processing requirement.
Best for: Enterprise businesses, multi-country operations, unified commerce (online + in-store).
Limitation: Not designed for small businesses (minimum processing threshold). Less plug-and-play than Stripe — better suited for businesses with engineering resources.
Worldpay
Worldpay (now part of FIS) is the UK's largest merchant acquirer by volume. It processes payments for businesses of all sizes, from sole traders to enterprise retailers. Its strength is breadth: card terminals, online payments, phone payments, and multi-currency processing.
Fees: From 0.75% + 10p per transaction, plus monthly fees from £19.95. Pricing is negotiable for higher volumes.
Best for: UK businesses with in-store payments, high-volume retail, businesses wanting a traditional merchant acquirer.
Limitation: Legacy infrastructure can mean slower onboarding and less modern developer tools compared to Stripe or Adyen. For a detailed comparison, see Adyen vs Worldpay.
Checkout.com
Checkout.com is a high-growth payment processor focused on performance. Its claim: higher approval rates than competitors through intelligent routing and direct acquiring relationships. It's gained significant traction with fast-growing online businesses and marketplaces.
Fees: Interchange + ~0.20% per transaction. No monthly fee.
Best for: High-growth e-commerce, marketplaces, businesses where approval rates directly impact revenue.
Limitation: Less brand recognition with SMBs. No in-store POS offering. For more detail, see Adyen vs Checkout.com.
Square
Square combines a payment gateway with POS hardware in one package. For small UK businesses that need both online and in-store payments, Square is the simplest all-in-one option.
Fees: 1.75% for in-person. 2.5% for online/invoices. No monthly fee for basic plan.
Best for: Small businesses, restaurants, retail, market traders.
Limitation: Flat pricing is expensive at scale. Limited customisation compared to API-first providers. Not suitable for enterprise or platform use cases.
How to Choose the Right Gateway
Small business, low volume: Square or SumUp for simplicity. PayPal if your customers expect it.
Online-only, growing: Stripe for developer experience. Checkout.com if approval rates matter.
High volume: Adyen or Worldpay with interchange-plus pricing.
Multi-country: Adyen for local acquiring. Stripe for broad country coverage.
In-store + online: Square for small. Worldpay or Adyen for enterprise.
Direct Debit / recurring: GoCardless for bank-to-bank. Stripe Billing for card-based subscriptions.
Payment Gateways for Platforms
If you're building a software platform that needs to embed payments for your users, the single-gateway approach breaks down fast. Your first customer uses Stripe. Your second needs Adyen. Your third has a Worldpay contract they can't change.
Instead of building separate integrations to each gateway, platforms use a payment layer — a single integration that connects to 40+ gateways and handles PCI compliance, merchant onboarding, and multi-channel payment capture.
See What Is Embedded Payments? for a full guide to how platforms approach payment gateway selection.
FAQ
What's the cheapest payment gateway in the UK?
For low volume: SumUp (1.69%, no monthly fee). For high volume: Adyen or Worldpay with interchange-plus pricing (total costs from ~0.3% for UK debit cards).
Do I need a merchant account to use a payment gateway?
Not with PSPs like Stripe, Square, or PayPal — they provide an aggregated merchant account. With traditional acquirers like Worldpay, the merchant account and gateway are bundled together.
Can I use multiple payment gateways?
Yes. Many businesses use multiple gateways for redundancy, cost optimisation, or to support different channels (e.g., Stripe online + Worldpay in-store).
What about security (PCI compliance)?
All major gateways handle PCI compliance for the card data they process. As a merchant, using a hosted payment page or tokenisation reduces your PCI scope to the minimum (SAQ-A).
Need help comparing payment options? Browse all supported payment providers or see payment services for merchants.