A payment gateway is the tool that takes your customer's card information and sends it securely to the bank for approval

Think of a payment gateway as a find tunnel between your online store and the banking system. When a customer enters their credit card number on your checkout page, the gateway encrypts that information — scrambles it so no one can read it — and passes it to the customer's bank and your bank to confirm the transaction is real and the funds are available. The gateway then tells your store whether the payment went through or was declined, usually within a few seconds.

You do not handle the card number yourself. The gateway does. This protects both you and your customer, because card data never sits on your store's computer where a hacker might find it. The gateway also handles the technical work of talking to different banks, different card types, and different countries' payment rules — work that would be impossible for a small store to do alone.

Key Takeaways

  • A payment gateway encrypts card information and sends it to banks for approval, so you never store the raw card data yourself.
  • The gateway handles communication with different banks and card networks, which means your store does not have to build those connections.
  • Most gateways charge a percentage of each transaction (often 2 to 3 percent) plus a small flat fee per transaction.
  • Popular gateways include Stripe, Square, PayPal, and Authorize.net, each with different pricing and features for different store sizes.
  • Your gateway choice affects how fast customers see their payment confirmed and how many payment methods (cards, digital wallets, bank transfers) your store can offer.

What happens between the moment a customer clicks "pay" and when they see "order confirmed"

The customer enters their card details on your checkout page. The gateway when ready encrypts that information using a security standard called SSL encryption — the same technology that protects your bank's website. The encrypted data travels to the gateway's servers, not to your store's servers.

The gateway then contacts the customer's bank (the issuing bank) and your bank (the acquiring bank) to ask: "Does this person have a valid card? Do they have enough money? Is this transaction suspicious?" The issuing bank responds yes or no within seconds. If yes, the gateway tells your store the payment is approved, your store shows the customer a confirmation page, and the money begins moving from the customer's account to yours — though the actual transfer of funds takes a day or two and is handled by a separate system called a payment processor.

If the bank says no — the card is expired, the address does not match, the customer has insufficient funds — the gateway tells your store when ready, and your store shows the customer an error message. The customer can try again with a different card or payment method.

Why you need a gateway even if you use a payment processor

A payment processor and a payment gateway sound like the same thing, but they do different jobs. The gateway is the security checkpoint that approves or declines the transaction in real time. The processor is the accountant that settles the money after approval — it collects all your transactions from the day, batches them, and moves the funds into your bank account.

Some companies, like Stripe or Square, sell you both the gateway and the processor as one package, so you do not see the difference. Other companies sell only one or the other. Either way, you need both for a complete transaction. The gateway approves it; the processor moves the money.

How much a payment gateway costs

Most gateways charge you a percentage of each transaction — typically 2 to 3 percent — plus a flat fee per transaction, often 30 cents. So if a customer buys something for $100, you might pay $2.30 to $3.30 to process that payment. Some gateways also charge a monthly fee, usually $20 to $50, whether you process any transactions or not.

The exact rate depends on the gateway you choose, the type of card the customer uses (a rewards card might cost you more than a basic card), and whether the customer is physically present (swiping in your store) or remote (entering details online). International transactions usually cost more. Some gateways offer lower rates if you process a high volume of transactions each month.

Before you sign up, ask the gateway for their full pricing sheet. Look for the transaction percentage, the per-transaction fee, any monthly fee, and any fees for refunds, chargebacks, or failed transactions. A gateway that looks cheap at 2 percent might charge $50 a month, while one at 2.9 percent might have no monthly fee — which is cheaper depends on your sales volume.

Popular gateways and what makes them different

Stripe is built for online stores and software companies. It charges 2.9 percent plus 30 cents per transaction with no monthly fee. It works with most shopping platforms (Shopify, WooCommerce, BigCommerce) and handles many payment methods including cards, digital wallets like Apple Pay, and bank transfers in some countries.

Square started with in-person payments but now handles online payments too. It charges 2.9 percent plus 30 cents for online card payments and offers a free point-of-sale system if you also process in-person payments. Square is popular with small businesses that sell both online and in a physical location.

PayPal charges 2.99 percent plus 30 cents per transaction. It is well-known and many customers trust it, but it is slower to set up and has stricter rules about what you can sell. PayPal works well if your customers already have PayPal accounts.

Authorize.net is older and more complex but offers lower rates (around 2.9 percent) if you process high volume. It requires more technical setup and is more common in larger businesses than small stores.

What payment methods your gateway can offer

Not every gateway supports every payment method. Most support credit and debit cards (Visa, Mastercard, American Express, Discover). Many now support digital wallets like Apple Pay, Google Pay, and PayPal, which let customers pay by tapping their phone instead of typing a card number. Some gateways in Europe or Asia support bank transfers or local payment methods like iDEAL or Alipay.

The more payment methods your gateway supports, the more customers can check out without friction. A customer who does not have a credit card but has Apple Pay will abandon your store if you only accept cards. Before you choose a gateway, list the payment methods your customers are likely to use, then check whether the gateway supports them.

Security and compliance: what the gateway handles for you

Payment gateways are required to follow a security standard called PCI DSS (Payment Card Industry Data Security Standard). This standard says that card data must be encrypted, stored securely, and never written down in plain text. The gateway handles all of this for you.

Because the gateway encrypts the card information before it reaches your store, your store does not have to store card numbers at all. This means you do not have to pass a PCI audit yourself — the gateway does. This is a huge advantage for small businesses, because PCI compliance is expensive and complicated.

You still have to keep your store's software updated and use strong passwords, because a hacker could break into your store through other routes (like an outdated plugin). But the gateway protects the most sensitive part: the card data itself.

Frequently Asked Questions

What is the difference between a payment gateway and a shopping cart?

A shopping cart is where customers add items and see their total. A payment gateway is what processes the payment after they click checkout. You need both. Many shopping platforms (like Shopify) include a shopping cart and let you plug in a gateway like Stripe. Some gateways also have their own shopping cart built in.

Can I use multiple payment gateways on one store?

Yes, but it is usually unnecessary and adds complexity. Most stores use one gateway that supports multiple payment methods (cards, digital wallets, etc.). You might use two gateways only if one does not support a payment method your customers need, or if you are testing a new gateway before switching.

How long does it take for the money to show up in my bank account?

The gateway approves the payment in seconds, but the actual money transfer takes one to three business days. This is handled by the payment processor, not the gateway. Some gateways offer faster payouts (next day) for a higher fee. Check the gateway's payout schedule before you sign up.

What happens if a customer disputes a charge?

The customer contacts their bank and says the charge was unauthorized or the product never arrived. The bank then contacts your gateway and asks for proof that the transaction was legitimate. The gateway forwards the dispute to you. You have a window (usually 7 to 10 days) to provide evidence — like a shipping receipt or email confirmation. If you do not respond or your evidence is weak, you lose the money and pay a chargeback fee, usually $15 to $100.

Do I need a separate gateway if I sell internationally?

Most modern gateways support international transactions, but rates and available payment methods vary by country. Stripe, for example, supports cards in most countries but bank transfers only in some. Before you expand internationally, check your gateway's documentation for the countries you plan to sell to, or contact their support team.