Ecommerce Payment Processing Explained: Fees and Choices

What actually happens when a customer pays

From the shopper’s side, checkout feels instant: they enter a card, tap a button, and see a confirmation. Underneath, a short relay race is running. Understanding the runners is the fastest way to understand where your money goes.

When a customer submits payment, the request first reaches a payment gateway, which encrypts the card details and passes them along. The gateway hands off to a payment processor, which routes the request to the relevant card network such as Visa or Mastercard. The network asks the customer’s bank, the issuing bank, whether the funds are available and the card is valid. If the answer is yes, an approval travels back down the same chain, and the sale is authorized. Later, in a separate step called settlement, the money is actually pulled from the issuing bank and deposited into your bank, the acquiring bank.

Each of those parties does real work, and each takes a share. That is the honest reason payment processing is never free: you are renting a global network that clears funds in seconds and carries the risk of fraud and disputes.

Where the fees come from

It helps to stop thinking about “the fee” and start thinking about a fee structure. Most ecommerce sellers encounter a few recurring components, and knowing their names makes provider comparisons far less confusing.

• Interchange is the portion set by the card networks and paid to the issuing bank. It is the largest piece of a typical card fee and varies by card type, with rewards and business cards usually costing more than basic debit.
• Network assessment is a smaller fee the card network keeps for itself.
• Processor margin is what your processor or platform adds for its service. This is the part that differs most between providers and the part you have the most leverage over.

On top of those, most providers charge a small fixed fee per transaction, which matters a lot for low-value orders and barely registers for high-value ones. There are also situational charges: currency conversion when you sell across borders, extra costs for manually keyed or international cards, monthly platform or gateway fees, and dispute-related fees when a chargeback occurs.

Because interchange is passed through to the banks and networks, no processor can make it disappear. When you compare providers honestly, you are mostly comparing their margin and their fixed per-transaction fee, plus how they handle the situational charges.

Flat-rate versus interchange-plus pricing

Providers generally package all of this into one of two pricing shapes, and the better fit depends on your numbers rather than on which sounds cheaper.

Flat-rate (blended) pricing

Here the provider quotes a single percentage plus a fixed fee that applies to essentially every card. It hides interchange variation inside one predictable rate. The appeal is simplicity: one number, easy forecasting, no reconciliation of card types. The trade-off is that you are paying an average, so cards that would have been cheap under interchange subsidize the expensive ones.

Interchange-plus pricing

Here the provider passes interchange and network fees straight through and adds a clearly stated margin on top. Your statement itemizes the pieces. The appeal is transparency and often a lower effective cost at scale, because you stop overpaying on cheap cards. The trade-off is complexity: your effective rate now moves with your card mix, and statements take more effort to read.

As a rough rule of thumb, very new or low-volume stores often prefer flat-rate for its simplicity, while stores with steady, higher volume frequently save money by moving to interchange-plus. There is no universally correct answer, only the answer your own transaction data supports.

All-in-one platforms versus assembled stacks

Separate from pricing shape is the question of how much you build yourself. Broadly, you are choosing between two approaches.

An all-in-one provider bundles the gateway, processing, fraud tools, and reporting into one account you can switch on quickly. You get a working checkout in a fraction of the time, plus dashboards and support in one place. The trade-off is usually a slightly higher blended margin and less control over the deepest configuration.

An assembled stack lets you pair a gateway of your choice with a separate processor or negotiate directly for interchange-plus, wiring the pieces together yourself. This can lower your effective cost and give you flexibility, but it demands engineering time, ongoing maintenance, and someone who understands the plumbing when something breaks.

The right call is an operational judgment, not a purely financial one. If you have limited technical capacity, the time you save with an all-in-one provider is often worth more than the margin you might shave with a custom stack. As volume grows and a dedicated team appears, revisiting that choice becomes worthwhile.

The costs that hide behind the base rate

Sellers often obsess over the headline percentage and then lose more margin to costs that never appear in the comparison table. A few deserve deliberate attention.

• Chargebacks and disputes. When a customer disputes a charge, you can lose the sale, the product, and a dispute fee, and repeated disputes can raise your risk profile with the processor. Clear product descriptions, a recognizable billing descriptor, and responsive support prevent more of these than any tool.
• Failed and declined payments. Every legitimate sale that fails at checkout is lost revenue. Offering more than one payment method and handling retries gracefully recovers orders you have already earned.
• Cross-border and currency fees. Selling internationally introduces conversion costs and sometimes higher rates on foreign cards. If a meaningful share of your customers is abroad, this belongs in your cost model from the start.
• Payout timing. How quickly funds land in your bank affects cash flow, especially for small operations buying inventory. A slightly cheaper provider with slower payouts can be the more expensive choice in practice.

Choosing a setup you will not regret

Rather than chasing the lowest advertised rate, work from your own operating reality. Start with three numbers you already have or can estimate: your average order value, your monthly transaction volume, and the share of customers who pay from another country. Those three shape almost every decision above.

Then weigh them against your capacity. A useful comparison table looks less like a ranking of rates and more like this:

Finally, read the full fee schedule, not the marketing page. Confirm how disputes, refunds, international cards, and payouts are handled before you commit, and re-run the comparison once a year as your volume changes. Payment processing rewards the operator who treats it as an ongoing decision rather than a one-time signup.