What is a card machine?
A card machine (also called a card terminal or card reader) is the physical device a customer uses to pay you in person, by tapping their contactless card, inserting their chip card, or holding their phone (Apple Pay, Google Pay) against it. A payment gateway is the software equivalent for online payments, where the customer types their card details into your website checkout. Both connect through an acquirer (Visa or Mastercard partner) that processes the transaction and pays the money into your merchant account (your business bank account, in most modern setups).
The four UK card-payment terms, explained
Card machine
Also called: card terminal, card reader, PDQ machine, EPOS reader
A physical device a customer uses to pay you in person, by tapping their contactless card, inserting their chip card, or holding their phone (Apple Pay, Google Pay) against it. The machine reads the card details, authorises the transaction with the customer's bank, and prints or emails the receipt.
Examples: Dojo Go, SumUp Solo, Square Terminal, Zettle Reader 2, Stripe Reader S700, Tap to Pay on iPhone (which uses the iPhone itself as the card machine).
Who needs one: You sell to customers in person, at a till, in a shop, restaurant, salon, mobile (taxi, dog grooming, plumbing) or market stall.
Payment gateway
Also called: online payment processor, checkout gateway
Software, not a physical device, that takes card details on your website or app at checkout. The gateway captures the card details on a hosted page (Stripe Checkout, Shopify Payments) or directly in your checkout form (Stripe Elements, Adyen Components) and passes them to the bank for authorisation.
Examples: Stripe Checkout, Adyen Web, Shopify Payments, Square Online, GoCardless, PayPal Checkout, Opayo, Mollie.
Who needs one: You sell online, run an ecommerce store, charge subscription billing, take donations, or run a marketplace. The customer is on your website at the point of payment, not in front of you.
Merchant account
Also called: merchant services account, acquiring account
The bank account that receives the money from card transactions, after Visa, Mastercard or AMEX have processed them and the acquirer has taken its cut. Most modern UK providers (Dojo, SumUp, Square, Stripe) bundle a merchant account into the same product as the card machine or gateway, so you don't see it as a separate setup. Traditional providers (Worldpay, Barclaycard) make you open a separate merchant account.
Examples: Bundled into Dojo, SumUp, Square, Stripe, Tide, Revolut. Separate for Worldpay, Barclaycard, Elavon.
Who needs one: Always. If you accept card payments, you have a merchant account, whether you see it as a separate thing or not.
Acquirer
Also called: acquiring bank, merchant acquirer, card processor
The bank or company that contracts with you (the merchant) and with Visa or Mastercard, takes responsibility for processing your card transactions, manages chargebacks, and pays you the money. The acquirer is the entity that signs you up. Some acquirers sell directly (Worldpay, Adyen, Tyl). Others sell through "ISOs" or partners (Dojo, SumUp, Square, Stripe all act as acquirer-or-ISO depending on plan).
Examples: Worldpay, Barclaycard, Elavon, Adyen, Stripe, Tyl by NatWest, Lloyds Cardnet, plus Dojo, SumUp, Square, PayPal Zettle acting as acquirers or ISOs.
Who needs one: Always, but you mostly don't see them. The acquirer is the entity that signs your terms-and-conditions and pays out the money.
In one sentence
Card machine for in-person sales. Payment gateway for online sales. Both connect through an acquirer to your merchant account.
Most UK SMB owners only need one or the other. If your customers pay in person, you need a card machine. If they pay on your website, you need a payment gateway. If you do both, one acquirer can run both rails: Stripe, Adyen, Square or Worldpay are the four that handle the in-person plus online combination well in 2026.
Get matched in 2 minutesFrequently asked questions
What is the difference between a card machine and a card terminal?
There is no difference. "Card machine", "card terminal", "card reader" and "PDQ machine" all describe the same thing: the physical device that a customer uses to pay you in person. UK shop owners say "card machine"; the industry says "card terminal"; older bank-acquirer documentation says "PDQ"; some Americans say "card reader". Same device.
Do I need a separate merchant account if I have a card machine?
Probably not in 2026. Modern UK providers (Dojo, SumUp, Square, Stripe, Tide, Revolut, Tap to Pay on iPhone) bundle the merchant account into the same product as the card machine. You sign one contract and the money lands in your business bank account. Traditional bank-acquirer providers (Worldpay, Barclaycard, Elavon) historically required a separate merchant account, but their newer SMB products bundle it too.
What is the difference between a card machine and a payment gateway?
A card machine is a physical device used when the customer is in front of you and uses their card in person. A payment gateway is software used when the customer is on your website and types their card details into a checkout form. Card machines are "card-present" transactions; payment gateways are "card-not-present" transactions. Different pricing, different fraud risk, different settlement schedules. If you sell both in person and online, you want an acquirer that runs both rails (Stripe, Adyen, Square).
What does PDQ stand for?
PDQ stands for "Process Data Quickly". It was a branded card-terminal product line in the 1990s, retired decades ago, but the name stuck and many UK shop owners and older bank-acquirer documentation still call card terminals "PDQ machines". In 2026 "card machine" or "card terminal" is more standard usage.
What is contactless and Tap to Pay?
Contactless is the wireless payment standard where the customer holds their card or phone near the card machine instead of inserting and entering a PIN. UK contactless transactions are capped at £100 per transaction (raised from £45 in October 2021); above £100 the customer must use chip-and-PIN. Apple Pay and Google Pay are contactless via a phone, with the customer authenticating via Face ID, Touch ID or device PIN; they have no £100 cap because the device authentication satisfies the limit rules. "Tap to Pay on iPhone" is the related Apple feature where the iPhone itself acts as the card machine, accepting contactless cards directly.
How much does a card machine cost?
Hardware: £49 (Tide Card Reader, Revolut Card Reader) to £329 (Stripe Reader S700) one-off, or zero for Tap to Pay on iPhone if you already have a compatible iPhone. Per-transaction rate: 0.74% (Tyl by NatWest, conditional) to 1.95% (SumUp at lowest plan) on UK consumer-card transactions. Monthly fee: zero (SumUp Solo, Square Terminal, Tide, Revolut) to £25+ (some Dojo, Worldpay and Adyen plans). Contract: zero (most modern providers) to 12 to 36 months (Worldpay, Barclaycard legacy). The "best card machine" for you depends on monthly card volume, average transaction size, contract appetite and trade. Use our /fees-calculator/ to model the blended cost.
Can I use one card machine for my shop and my website?
Not directly, but yes via one acquirer running both rails. The card machine handles in-person (card-present) and a separate gateway handles online (card-not-present), but both can sit under one acquirer for unified reporting and reconciliation. The acquirers that run both rails well in 2026 are Stripe (Stripe Reader S700 plus Stripe Checkout), Adyen (Adyen Terminal plus Adyen Web), Square (Square Terminal plus Square Online), and Worldpay. SumUp, Dojo and Tide are in-person-led; Shopify Payments, GoCardless and Opayo are online-only.
Do I need a card machine if I only take card on my phone?
No, that is Tap to Pay on iPhone, which uses your iPhone itself as the card machine. iPhone XS or newer running iOS 16.4 or later, paired with an acquirer that supports the feature (SumUp, Square, Zettle, Stripe, Tide or Revolut as of 2026). Tap to Pay on Android is also rolling out via Google Wallet with Adyen, Stripe and others. The customer taps their contactless card or phone against your iPhone screen; the transaction processes the same way as a hardware terminal.
Reviewed by Oliver Mackman. Last reviewed: 2026-05-11.