A credit card processor is the company that handles the communication between a merchant, the customer’s bank, and the merchant’s bank every time someone pays with a card. It’s the behind-the-scenes service that verifies the card is valid, confirms funds are available, and moves money from the cardholder’s account into the business’s bank account. Every business that accepts credit or debit cards uses a processor, whether they realize it or not.
What a Processor Actually Does
When you swipe, tap, or type in a card number at checkout, the processor kicks off a chain of events that typically finishes in a few seconds. First, the processor takes the card details from the merchant’s terminal or website and sends an approval request through the card network (Visa, Mastercard, American Express, or Discover) to the bank that issued the customer’s card. That bank checks three things: the card is valid, the cardholder’s identity matches (usually by comparing the billing address), and the account has enough funds or available credit. If everything checks out, the bank sends an authorization code back through the network to the processor, which relays the approval to the merchant.
That approval is just the first half. The second half, called settlement, is when money actually moves. After the transaction is authorized, the processor coordinates the transfer of funds from the customer’s bank to an intermediary account held by the merchant’s acquiring bank. From there, the money lands in the business’s regular bank account, usually within a few days.
How Processors Differ From Payment Gateways
If you sell in person only, a processor paired with a card reader is all you need. But if you sell online, you also need a payment gateway, which is the digital equivalent of a physical card terminal. The gateway collects and encrypts the customer’s card information on your website, then hands it off to the processor to communicate with the banks and move the funds.
In practice, you rarely have to shop for these separately. Most major processors now operate their own gateways, and many gateway platforms bundle in processing. If you sign up with a company like Stripe or Square, you’re getting both in one package.
Types of Processors
There are two broad categories of processor, and they serve different types of businesses.
Traditional merchant account providers set up a dedicated merchant account in your business’s name. You go through an application and underwriting process, which can take days or longer. In exchange, you often get lower per-transaction fees and more flexibility in how your pricing is structured. This route tends to suit businesses with higher sales volumes that benefit from negotiated rates.
Payment aggregators (sometimes called payment service providers) take a different approach. Companies like Square, Stripe, and PayPal pool many merchants under a single master account instead of creating an individual one for each business. The upside is speed: you can start accepting payments almost immediately with minimal paperwork. Aggregators also make it easy to accept credit cards, debit cards, digital wallets, and bank transfers without separate integrations. The trade-off is that their pricing is typically a flat rate per transaction, which can be more expensive at higher volumes. They also won’t pay interest on funds held in your account the way a bank would.
How Processing Fees Work
Every time you accept a card payment, a slice of the transaction goes to the processor, the card network, and the issuing bank. How those fees are packaged depends on the pricing model your processor uses.
- Flat-rate pricing bundles all the underlying costs into a single, predictable rate per transaction. You might pay something like 2.6% plus 10 cents on every sale, regardless of the card type. This is the model most aggregators use, and it’s easy to understand, though not always the cheapest.
- Interchange-plus pricing separates the card network’s base fee (called the interchange rate, which varies by card type and transaction method) from the processor’s own markup. You might see a markup of 0.4% plus 8 cents on top of whatever the interchange rate happens to be. This model offers more transparency and often saves money for businesses processing larger volumes.
- Subscription-based pricing charges a flat monthly fee for access to the processing service, then passes interchange costs through at cost or with a small per-transaction fee. This can be the cheapest option for high-volume merchants willing to pay a monthly commitment.
The right model depends on your sales volume and average transaction size. A coffee shop processing hundreds of small transactions has different math than a furniture store processing a handful of large ones.
Hardware and Software You’ll Need
What sits between your customer’s card and your processor depends on how you sell.
For in-person sales, you’ll need a card reader or point-of-sale terminal. These range from small mobile readers that plug into a phone or tablet to full countertop terminals with built-in screens and receipt printers. Most processors sell or lease their own hardware, and some include a basic reader for free when you sign up.
For online sales, the processor’s payment gateway handles card capture through your website or app. Many processors provide prebuilt checkout pages, plugins for popular e-commerce platforms, or APIs for custom integrations.
There’s also a middle option called a virtual terminal, which lets you log into a web dashboard and manually key in a customer’s card number, expiration date, and CVV. Virtual terminals are useful for phone orders, invoices, or situations where a physical card reader isn’t available. Many processors include virtual terminal access as part of their standard service.
How to Choose a Processor
Start with how and where you sell. A brick-and-mortar shop that never takes online orders has simpler needs than an e-commerce brand shipping nationwide. If you do both, look for a processor that handles in-person and online payments through a single account.
Compare pricing models against your actual sales patterns. If your monthly volume is modest, flat-rate pricing keeps things simple and predictable. If you process tens of thousands of dollars a month, interchange-plus or subscription pricing will likely save you money over time.
Look at what’s included beyond basic processing. Some providers bundle invoicing, inventory management, analytics, and customer loyalty tools into their platform. Others keep things lean and charge less. Pay attention to contract terms as well. Aggregators typically operate month to month with no long-term commitment, while traditional merchant account providers sometimes require contracts with early termination fees.
Finally, check how quickly funds reach your bank account. Most processors deposit within one to three business days, but some charge extra for same-day or next-day transfers. If cash flow timing matters to your business, that detail is worth comparing before you sign up.