What a payment gateway does and why you need one

A payment gateway is the tool that connects your online store to the banking system so customers can pay you by card, digital wallet, or bank transfer. It sits between your website and your payment processor — the company that actually moves money from the customer's account to yours. Without a gateway, you have no way to accept payments online.

When a customer enters their card details on your checkout page, the gateway encrypts that information, sends it to the processor for approval, and tells your store whether the transaction went through. The whole thing takes a few seconds. The gateway also stores transaction records, handles refunds, and protects both you and your customer from fraud.

You need a gateway even if you use a hosted platform like Shopify or WooCommerce — those platforms either provide their own gateway or let you choose from a list of approved ones. If you build a custom store, you pick the gateway yourself.

Key Takeaways

  • A payment gateway encrypts customer payment information and routes it to your processor, then reports whether the transaction succeeded.
  • Most gateways charge a percentage of each transaction (typically 2–3%) plus a small per-transaction fee, though some charge monthly flat rates instead.
  • Hosted platforms like Shopify include a gateway; custom stores require you to integrate one yourself or hire a developer to do it.
  • PCI compliance — a security standard for handling card data — is mandatory, and most gateways handle the technical side for you.
  • Choosing a gateway depends on your sales volume, the payment methods you want to offer, and whether you need international transactions.

How payment gateways charge and what the costs add up to

Most gateways use a transaction-based pricing model: they take a percentage of the sale (usually 2.2–2.9%) plus a fixed fee per transaction (typically $0.30). So a $100 sale might cost you $2.50 to $3.20 in gateway fees alone. Some gateways also charge a monthly account fee, which can range from $0 to $50 depending on the provider and your sales volume.

A few gateways offer flat-rate monthly pricing instead — you pay a set amount each month regardless of transaction volume. This model works if you have predictable, consistent sales, but it becomes expensive if your volume is low or seasonal.

International transactions often carry higher fees because the gateway has to handle currency conversion and cross-border compliance. If you sell globally, ask your gateway what the markup is on foreign cards before you sign up.

The gateway fee is separate from what your processor charges and separate from what your bank charges. You may end up paying three different entities for one transaction, so read the full fee schedule before committing.

Hosted platforms versus custom integration

If you use Shopify, WooCommerce, BigCommerce, or another hosted platform, the gateway is usually built in. Shopify Payments is Shopify's own gateway and is the default option; WooCommerce works with Stripe, Square, PayPal, and others. You don't install anything — you just connect your bank account and turn it on.

If you build a custom store or use a platform that doesn't include a gateway, you have to integrate one yourself. This means adding code to your checkout page that talks to the gateway's servers. Most gateways provide documentation and code libraries to make this easier, but if you're not a developer, you'll need to hire one. Integration typically takes a few hours to a few days depending on complexity.

Hosted platforms usually charge slightly higher gateway fees than you'd pay integrating directly, but you avoid the developer cost and the ongoing maintenance. For most small stores, that trade-off is worth it.

Payment methods: cards, wallets, and bank transfers

Most gateways accept credit and debit cards (Visa, Mastercard, American Express, Discover). Many also support digital wallets like Apple Pay, Google Pay, and PayPal, which let customers pay without entering card details. Some gateways add bank transfer options (ACH in the US, SEPA in Europe) or buy-now-pay-later services like Afterpay.

The more payment methods you offer, the fewer customers abandon their cart at checkout. But each method may have its own fee structure and settlement timeline. A bank transfer might take 3–5 days to arrive, while a card payment settles in 1–2 days. Check what your gateway supports and what the timing and costs are for each option.

International gateways often support local payment methods in each country — iDEAL in the Netherlands, Alipay in China, Klarna in Scandinavia. If you sell to specific regions, look for a gateway with strong local coverage.

PCI compliance and fraud protection

PCI DSS (Payment Card Industry Data Security Standard) is a set of rules that anyone handling card data must follow. It covers how you store information, who can access it, how you encrypt it, and how you test your systems for vulnerabilities. Violating PCI compliance can result in fines from your processor or your bank.

Most modern gateways handle PCI compliance for you by never storing raw card data on your servers. Instead, the gateway collects the card details, encrypts them immediately, and stores them in its own secure vault. Your store only sees a token — a reference number that lets you charge the card again without storing the actual number.

Beyond PCI, gateways offer fraud detection tools: they flag suspicious transactions (a $5,000 order from a new customer in a different country), check for stolen cards, and let you set rules for what to block. Some gateways use machine learning to spot patterns you wouldn't catch manually.

Settlement: when money actually reaches your account

Settlement is the process of money moving from the customer's bank to yours. It's not instant. Most gateways settle transactions within 1–2 business days, but some take 3–5 days. A few hold funds for longer if they detect high risk or if you're a new merchant.

Gateways also handle chargebacks — when a customer disputes a charge with their bank and the bank pulls the money back. You lose the sale and usually pay a chargeback fee ($15–$100). If your chargeback rate gets too high, your processor can terminate your account. Gateways provide tools to fight chargebacks (uploading proof of delivery, customer communication, etc.), but prevention is cheaper than fighting.

Some gateways offer instant payouts for an extra fee, usually 1–2% of the transaction. This is useful if you need cash flow quickly, but it's expensive at scale.

Choosing a gateway for your store

Start by asking: What platform am I using? If you're on Shopify or WooCommerce, your options are already narrowed. If you're custom-built, you have more freedom but also more responsibility.

Next, consider your sales volume and growth. A gateway that's cheap at $10,000 per month might be expensive at $100,000 per month. Some gateways offer volume discounts; others don't. Ask what your effective rate will be at your projected sales level.

Then think about geography. Do you sell only in the US, or internationally? Some gateways (Stripe, PayPal) work in many countries; others are regional. If you sell to Europe, you need a gateway that handles SEPA and understands GDPR. If you sell to Asia, you need local payment methods.

Finally, test the integration and support. Can you get a sandbox account to test before going live? Does the gateway have good documentation? Is there a support phone number, or only email? A cheap gateway with no support can become expensive when something breaks.

Frequently Asked Questions

Can I use multiple payment gateways on one store?

Yes. Many stores use one gateway for cards and another for PayPal or digital wallets. This spreads risk and can reduce fees if different gateways have different rates for different payment methods. Your platform has to support multiple gateways, and you'll need separate accounts with each one.

What happens if a customer's card is declined?

The gateway tells your checkout page the transaction failed, and the customer sees an error message. They can try a different card or payment method. No money moves. You don't pay a fee for a declined transaction, though some gateways charge a small fee for the attempt itself.

Do I need a separate merchant account?

Most modern gateways (Stripe, Square, PayPal) don't require a separate merchant account — they handle that relationship for you. Older gateways sometimes do. Ask the gateway directly; if they say you need one, they'll tell you how to set it up.

What's the difference between a gateway and a processor?

The gateway is the software that collects payment information and routes it. The processor is the company that actually moves the money. Some companies (Stripe, Square) act as both; others are just one or the other. You only interact with the gateway; the processor works behind the scenes.

Can I switch gateways without losing transaction history?

Yes, but it requires planning. Your old gateway will keep your historical records. Your new gateway starts fresh. You'll need to update your checkout page to point to the new gateway, and you may need to re-enter some settings. The switch itself usually takes a few hours, though you should test it first in a sandbox environment.