What you need to do before choosing a payment gateway

Before you pick a gateway and sign a contract, you need to know three things: what payment methods your customers will use, what your monthly transaction volume looks like, and whether you process in a single country or across borders. A gateway that works for a small local service business will not work the same way for an e-commerce store selling internationally. The setup process, fees, and technical requirements all depend on these facts.

You also need a merchant account — a special bank account that receives customer payments before they settle into your regular business checking account. Some payment processors (like Stripe or Square) bundle the merchant account into their service. Others require you to open one separately through a bank or a separate merchant services provider. Ask the gateway provider directly whether a merchant account is included or whether you need to open one yourself.

Finally, check your current point-of-sale system, website platform, or accounting software to see which gateways integrate with it. If you use Shopify, WooCommerce, QuickBooks, or Toast, the gateway must have a documented plugin or API connection for that platform. Trying to force a gateway into a system it does not connect to means manual data entry, lost transaction records, and reconciliation headaches.

Key Takeaways

  • You need a merchant account (which some processors include and others require you to open separately) before any gateway can process payments.
  • The gateway must integrate with your existing point-of-sale, website, or accounting software, or you will spend hours moving data between systems by hand.
  • Setup typically takes one to three weeks from application to first transaction, depending on how quickly you provide underwriting documents and how the processor verifies your business.
  • You will pay a combination of per-transaction fees (usually 2.2% to 3.5% plus $0.30 per card transaction), monthly minimums or flat fees, and sometimes setup or PCI compliance fees.
  • The processor will ask for your business license, tax ID, bank account details, and personal identification for the business owner before approving your account.

The application and underwriting process

Start by filling out the processor's online application. You will provide your business name, address, tax ID (EIN), the type of business you run, your estimated monthly transaction volume, and the average transaction size. The processor uses this information to assess risk — a business processing $50,000 a month in $5 transactions looks different from one processing $50,000 in a single annual transaction.

After you submit the application, the processor's underwriting team reviews your business. They may request your business license, articles of incorporation, a recent bank statement, and personal identification for the owner or authorized representative. This step usually takes three to five business days. If you are a sole proprietor, they may also run a personal credit check. If your business is new (less than six months old) or has a high-risk category (like e-commerce, subscription services, or travel), expect additional questions or requests for more documentation.

Once underwriting approves your account, the processor sends you login credentials and documentation for integrating the gateway into your system. If you use a hosted platform like Shopify or WooCommerce, the integration is usually a matter of entering an API key or authorizing the connection through your dashboard. If you have a custom-built website or point-of-sale system, your developer will need to use the processor's API documentation to build the connection. This technical setup can take anywhere from a few hours to a few weeks, depending on your system's complexity.

Connecting the gateway to your website or point-of-sale

The connection method depends on what system you use. If you run a Shopify store, you log into your Shopify admin, go to Settings > Payment Providers, and select your processor from the list. Shopify handles the technical connection; you just enter your account credentials. WooCommerce works similarly — you install the processor's plugin from the WordPress plugin directory, activate it, and enter your API keys. Square, Toast, and other point-of-sale systems have their own built-in gateways that are already active once your account is approved.

If you have a custom website or a system that does not have a pre-built integration, your developer will use the processor's API (Application Programming Interface) to build the connection. The processor provides API documentation that shows your developer how to send payment data securely, handle responses, and store transaction records. This route requires more technical work but gives you more control over the payment experience. Common processors with strong API documentation include Stripe, Authorize.Net, and PayPal Commerce Platform.

After the technical connection is live, run test transactions before you accept real payments. Most processors provide a sandbox environment — a copy of the live system where you can process fake transactions to confirm everything works. Use test card numbers provided by the processor (like 4111 1111 1111 1111 for Visa) to verify that payments are captured, refunds process, and transaction records appear in your dashboard. Only after successful test transactions should you switch to live mode and start accepting real customer payments.

Understanding fees and pricing models

Payment processors charge fees in several ways, and the total cost depends on your transaction mix. The most common model is interchange-plus pricing: you pay the card network's interchange fee (set by Visa, Mastercard, or Amex — typically 1.5% to 2.2% for credit cards, lower for debit) plus the processor's markup (usually 0.5% to 1%) plus a per-transaction fee (usually $0.20 to $0.30). A $100 credit card transaction might cost you $2.50 to $3.50 in fees.

Some processors offer flat-rate pricing instead: a single percentage (like 2.9%) plus a fixed per-transaction fee (like $0.30), regardless of card type. This is simpler to budget but usually costs more if you process a lot of debit cards or non-US cards, which have lower interchange rates. Other processors charge a monthly subscription (like $29 or $99 per month) plus lower per-transaction fees, which makes sense if you process high volume.

Beyond transaction fees, watch for hidden costs: setup fees (usually $0 to $100), PCI compliance fees (usually $10 to $30 per month if the processor handles compliance), monthly minimums (some processors charge a minimum fee even if you process nothing), and early termination fees (usually $0 to $300 if you close the account within a contract period). Ask the processor for a written fee schedule before you sign anything, and calculate what your actual monthly cost would be based on your expected transaction volume.

Security and PCI compliance requirements

PCI DSS (Payment Card Industry Data Security Standard) is a set of rules that anyone handling credit card data must follow. The rules exist to prevent card data theft. The good news: if you use a hosted payment form or a processor that handles the payment page, the processor is responsible for most PCI compliance. You do not store card numbers on your own servers, and you do not need to pass a full PCI audit.

If you build a custom payment form or store any card data yourself, you become responsible for PCI compliance, which means annual security audits, encryption requirements, and strict access controls. This is expensive and risky. For almost every business, the right choice is to use the processor's hosted payment form or a tokenization service, where the processor stores the card data and you only store a token (a reference number) that lets you charge the card again without storing the actual card number.

When you set up the gateway, the processor will ask you to agree to their PCI compliance terms and may require you to complete a self-assessment questionnaire (SAQ) that confirms you are following the rules. Some processors include PCI compliance in their service; others charge a monthly fee. Either way, the processor handles the heavy lifting. Your job is to use their payment form, not build your own, and to keep your login credentials secure.

Testing and going live

Before you process real customer payments, spend time in the processor's sandbox environment. Create a test merchant account (most processors provide this automatically), use test card numbers, and run through every payment scenario: a successful charge, a declined card, a refund, a partial refund, and a subscription renewal if you offer subscriptions. Check that transaction records appear in your dashboard, that your accounting software receives the data, and that customer receipts are formatted correctly.

Also test your error handling. What message does a customer see if their card is declined? Can they try a different card? What happens if the internet connection drops mid-transaction? The processor's documentation should explain how to handle these cases, and your developer should build those responses into your system before you go live.

Once testing is complete, switch your gateway to live mode. The processor will confirm this in writing or through your dashboard. Process a small real transaction (a few dollars) to confirm that money actually moves from the customer's card to your merchant account. Check your bank account after two to three business days to verify the deposit arrived. Only after you see real money in your account should you consider the setup complete.

Ongoing management and troubleshooting

After the gateway is live, your main tasks are monitoring transaction volume, watching for fraud, and reconciling payments with your accounting records. Log into your processor's dashboard regularly to review transaction reports, check for chargebacks (customer disputes), and confirm that deposits match your records. Most processors send a daily or weekly settlement report showing what transactions cleared and when the money will hit your bank account.

If a customer reports that a payment failed or was charged twice, the processor's dashboard will show you the transaction record and the reason for the failure. Common issues include insufficient funds, incorrect card details, or a mismatch between the billing address and the card's registered address. You can refund a transaction directly from the dashboard, usually within seconds, though the refund may take one to three business days to appear on the customer's card.

If you notice suspicious transactions (like multiple small charges from different cards in a short time), report them to the processor immediately. Most processors have fraud detection built in and will flag or block suspicious activity automatically. If your account is flagged for fraud, the processor may freeze your account temporarily while they investigate, so respond quickly to any requests for information.

Frequently Asked Questions

How long does it take from application to first transaction?

Typically one to three weeks. The application itself takes a few minutes, underwriting takes three to five business days, and technical setup takes anywhere from a few hours (if you use Shopify or WooCommerce) to a few weeks (if you have a custom system). The longest delays usually happen during underwriting if the processor needs additional documentation or if your business is in a high-risk category.

Do I need a separate merchant account, or does the processor provide one?

It depends on the processor. Stripe, Square, and PayPal include a merchant account in their service — you do not need to open one separately. Authorize.Net and some others require you to open a merchant account through a bank or a separate merchant services provider. Ask the processor directly before you sign up.

What happens if a customer disputes a charge?

The customer contacts their card issuer and reports the charge as unauthorized or incorrect. The processor notifies you of the dispute (called a chargeback), and you have a window (usually 7 to 10 days) to respond with evidence that the transaction was legitimate — like a signed receipt, shipping confirmation, or email correspondence with the customer. If you do not respond or your evidence is weak, you lose the money and may be charged a chargeback fee (usually $15 to $100).

Can I use the same gateway for online and in-person payments?

Yes, most modern processors support both. You can accept payments on your website through a hosted form and also accept card payments in person through a point-of-sale app or card reader. The same merchant account and gateway handle both, and all transactions appear in the same dashboard. Some processors charge different rates for in-person versus online transactions, so confirm the fee structure for both before you sign up.

What if my processor goes out of business or I want to switch?

Your customer data and transaction history stay with the processor — you cannot download it and move it to a new processor automatically. However, most processors will provide a transaction report or export if you request it. When you switch, you will need to update your website or point-of-sale system to use the new processor's gateway, which usually takes a few hours to a few days depending on your system. There may be an early termination fee if you are in a contract, so check your agreement before you switch.