Best Online Payment Gateways for UK Small Businesses 2026

Updated August 2026. A payment gateway is the technology that securely connects your online checkout with the systems that authorise and process the customer’s payment. Older guides often list dozens of gateway brands without explaining which ones are actually sensible for a UK SME.

For most small businesses, start by comparing Square, Stripe, PayPal/Braintree and the online option offered by your existing merchant provider. The right choice depends on your ecommerce platform, average order value, international sales and how much technical customisation you need.

What is a payment gateway?

When a customer enters card details online, the gateway securely passes the payment request into the processing chain. If you are unclear on how the merchant account fits in, see our ecommerce merchant accounts guide. the payment request into the processing chain and returns the approval or decline result to the website.

Modern providers can bundle the gateway with acquiring, fraud tools, tokenisation, wallets and settlement. That is why a merchant often sees one provider name rather than five separate payment companies.

Gateway versus processor versus merchant account

• Gateway: connects the checkout to the payment infrastructure.
• Processor: handles transaction messaging and processing.
• Acquirer or merchant arrangement: enables the merchant to accept and settle card payments.

Some suppliers provide all three in one package.

1. Square online payments

Square currently charges 1.4% + 25p for online transactions with UK cards and 2.5% + 25p for non-UK cards.

It is particularly attractive for small businesses already using Square in person because the same provider can cover POS, card readers, online checkout and payment links.

Square is not as developer-focused as Stripe, but many SMEs do not need deeply customised payment infrastructure.

See Square

2. Stripe

Stripe’s current UK standard pricing starts at 1.5% + 20p for standard UK cards. Premium UK cards and international transactions cost more.

Stripe is particularly strong when developers need control over:

• custom checkout;
• subscriptions;
• saved payment methods;
• marketplaces;
• platform payments;
• multi-currency sales;
• fraud rules;
• APIs and webhooks.

A small brochure-style website taking ten payments a month may not need that flexibility. A SaaS company probably will.

3. PayPal and Braintree

PayPal gives merchants access to a familiar wallet brand, payment buttons, hosted checkout and payment links. Braintree provides a more developer-oriented integration under the wider PayPal business offering.

Current UK Braintree standard pricing lists 1.9% + 20p for standard UK card and third-party digital-wallet transactions.

PayPal can increase customer choice, particularly where buyers already have PayPal accounts, but compare the exact merchant fee schedule for the payment method you plan to offer.

4. SumUp online payments

SumUp currently charges 2.50% for standard online payments. It is easy to add if you already use SumUp in person, but the convenience should be compared with lower public online rates available elsewhere.

Read our SumUp fees guide.

5. Your existing merchant-service provider

If you already process significant in-person turnover through Worldpay, takepayments or another acquirer, ask what online gateway and ecommerce pricing they can add.

A combined contract can simplify settlement and reporting. It may also unlock negotiated pricing that is not visible on a public website.

Do not assume the existing provider will automatically be cheapest. Get a separate online quote.

What happened to older gateway names?

Payment products change ownership, branding and market focus. For current provider comparisons rather than older gateway lists, see our payment processing companies guide. Older UK lists can include gateways that are no longer sold under the same name or are no longer a sensible mainstream recommendation.

For example, Sage Pay became Opayo and the market has continued consolidating since then. A 2018 list of “top 20 gateways” is not useful unless every provider is rechecked.

Choose from services actively onboarding UK merchants today.

Hosted checkout versus embedded checkout

A hosted checkout sends the customer to a payment page managed by the provider or embeds provider-controlled secure payment components. This is usually the simplest security model for a small business.

A deeply embedded custom checkout gives more control over branding and user experience but increases technical responsibility.

For most SMEs, prioritise a checkout that is fast, mobile-friendly and maintained by a reputable payments provider.

Payment links instead of a gateway

If you only take occasional remote payments, a full ecommerce integration may be unnecessary. Our accepting card payments guide covers payment links and other simple alternatives. Square, SumUp, PayPal and other providers let businesses generate payment links.

A builder can send a deposit link. A consultant can send a payment link with an invoice. A small club can send a link to members.

This gives customers a secure checkout without the business handling card details manually.

Virtual Terminal

A Virtual Terminal lets authorised staff enter a customer’s card details into the provider’s secure browser interface, normally for telephone orders.

Fees are usually higher than ecommerce checkout because the card is not present. Square currently charges 2.5% for its standard Virtual Terminal and manually entered transaction category.

PCI DSS

The current payment-card security standard is PCI DSS v4.0.1. The future-dated requirements became effective from 31 March 2025.

Using a hosted gateway can reduce your PCI scope because your own systems handle less payment-card data. Ecommerce merchants still need to protect their website against malicious scripts and other attacks.

See our PCI DSS guide.

Strong Customer Authentication and 3-D Secure

Modern gateways support 3-D Secure to handle authentication requirements on eligible online card transactions. The aim is to apply additional verification where needed without making every customer jump through unnecessary steps.

Ask how the provider handles exemptions and authentication rather than trying to build this yourself.

Fraud tools

Fraud prevention can be worth more than a tiny fee difference. Compare:

• 3-D Secure;
• AVS and card security checks;
• device and behaviour signals;
• custom risk rules;
• velocity controls;
• block and allow lists;
• chargeback management.

Stripe and other developer-focused processors offer sophisticated controls. Simpler providers aim to manage more of this automatically.

Recurring payments

If you sell subscriptions, memberships or regular services, check whether the provider supports tokenised stored payment methods and automatic recurring billing. Businesses with unusual risk profiles should also read our high-risk merchant accounts guide. tokenised stored payment methods and automatic recurring billing.

Also compare failed-payment recovery, customer-card updates, retries and subscription reporting. These features can matter more than the basic gateway fee.

International payments

If a material share of customers are overseas, model:

• international card surcharge;
• currency-conversion cost;
• supported settlement currencies;
• local payment methods;
• cross-border chargeback handling.

Square, Stripe and PayPal all charge differently for international transactions.

Average order value can change the cheapest provider

Compare £10 and £100 orders. A fixed 25p fee is 2.5% of a £10 basket but 0.25% of a £100 basket.

For low-ticket ecommerce, the pence component deserves just as much attention as the headline percentage.

Simple fee comparison

For 1,000 UK-card orders totalling £25,000:

• 1.4% + 25p = £350 + £250 = £600.
• 1.5% + 20p = £375 + £200 = £575.
• 2.50% with no separate fixed component = £625.

This simplified example ignores card-category differences, subscriptions, refunds and other fees. It shows why transaction count matters.

Integration with Shopify, WooCommerce and other platforms

Check whether the gateway has an actively maintained integration for your ecommerce platform. A slightly cheaper provider is poor value if the plugin is unreliable or your developer has to maintain a custom connection indefinitely.

For Shopify users, also compare the economics of Shopify Payments before adding a third-party provider.

Questions before choosing a gateway

• What is the fee for a standard UK consumer card?
• What is the fixed pence fee?
• How are overseas cards priced?
• Is 3-D Secure included?
• What fraud tools are included?
• Does it support my ecommerce platform?
• Can it handle subscriptions?
• How are refunds and chargebacks priced?
• How quickly are funds settled?
• Can I export complete transaction data?

Related Quotehunt guides

• Ecommerce merchant accounts
• Payment processing companies
• Credit card processing
• PCI DSS guide
• High-risk merchant accounts
• How to accept card payments

Our verdict

Square is the easiest online-payment benchmark for many small businesses, while Stripe is the strongest starting point when technical flexibility matters. PayPal belongs on the shortlist when customers expect PayPal or when its wider ecosystem is already important to the business.

Do not select a gateway because an old roundup calls it a “top 20 provider”. Use current UK availability, your average basket, transaction count and technical needs.

For more detail, read our ecommerce merchant account guide and payment processor comparison.