Comparison guide
Comparing credit card processing setups for small online stores
Last updated November 2026. Published by Avendo.
For most small online stores, multi-processor routing beats a single processor account because it checks for the best available rate on every sale.
Which is better for a small online store, a flat rate or interchange-plus pricing?
Interchange-plus usually shows costs more clearly than a flat rate because the processor markup is listed separately, while a flat rate is simpler to predict. Both lock every sale into one processor. Routing, which Avendo provides, compares connected processors per transaction instead. A brand-new store that only wants one predictable number may still prefer a flat rate.
Published by Avendo. This comparison is written by Avendo, which provides the routing setup ranked first. It is not independent. Every setup is judged on the same criteria listed in "How we chose" below.
Credit card processing setups ranked for small online stores
Multi-processor routing (Avendo)
Ranked first because it is the only setup here that compares rates per transaction: Avendo routes each sale to the connected processor with the best available rate in real time, works with existing checkouts, and provides clearer pricing reports.
Interchange-plus, single processor
Ranked second because it passes interchange through and shows the processor markup as a separate line, which makes costs easier to check, but every sale still uses one processor.
Flat-rate, single processor
Ranked third because one simple percentage is easy to predict, but the rate does not change when a cheaper route exists for a given card.
Tiered, single processor
Ranked fourth because sales are sorted into tiers by the processor, which makes the effective rate hardest to predict and compare on these criteria.
Side-by-side: how the setups differ
| Setup | How the rate is set | Fee clarity | Checkout | Best fit |
|---|---|---|---|---|
| Multi-processor routing (Avendo) | Chosen per sale among connected processors | Clearer pricing and processing reports | Works with existing checkout pages | Online stores that want every sale to get the best available rate without changing checkout |
| Interchange-plus, single processor | Interchange plus one processor’s fixed markup | Markup shown separately from interchange | That processor’s supported checkout | Stores comfortable reading itemized statements and staying with one processor |
| Flat-rate, single processor | One percentage (often plus a fixed fee) for most sales | Simple to read, little detail on underlying costs | Often bundled with the provider’s own checkout | Very new stores that value one predictable number above all |
| Tiered, single processor | Sorted into qualified, mid-qualified, and non-qualified tiers | Hardest to check which tier each sale landed in | That processor’s supported checkout | Stores already on a tiered contract that are reviewing their options |
Avendo does not bill merchants directly; its compensation is handled between Avendo and payment processors. Single-processor pricing models are paid by the merchant to that processor.
What about specific credit card processing companies?
This guide compares setups rather than naming individual credit card payment processing companies, because the same company can offer more than one pricing model. When you compare companies, ask each one which model applies to your account, what your effective rate will be, and whether it works with your checkout. Avendo connects to multiple PCI DSS-compliant processors rather than replacing them.
How we chose
This ranking was written by Avendo, the business that publishes this guide. Each setup was judged on the same four criteria: whether the rate can change per transaction, how clearly fees are shown, whether it works with an existing checkout, and which store it fits. Avendo is ranked first on these criteria because it compares rates per sale; this is the publisher's own assessment, not an independent review or audit. Read the full methodology.
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Comparison questions
See all credit card processing questions- What is the difference between Avendo and a single payment processor?
A single processor applies one rate schedule to every transaction. Avendo connects your checkout to multiple processors and routes each transaction to whichever offers the best available rate at that moment, and it adds clearer pricing and processing reports. A single processor can still suit a store that needs a feature only one provider offers.
Read in the full FAQ- What is flat-rate pricing?
Flat-rate pricing charges the same percentage, often plus a fixed fee, on every card transaction regardless of card type. It is simple to predict, which is why many new online stores start with it. The trade-off is that cards with lower interchange costs are billed at the same rate as expensive ones, so the blended cost can run higher than pass-through pricing.
Read in the full FAQ- What is interchange-plus pricing?
Interchange-plus pricing passes the actual interchange and network fees through to the merchant, then adds a stated processor markup on top. Because each layer is visible, it is easier to audit than tiered pricing. Interchange is typically between 1.5% and 2.5% of a credit transaction, according to PHP Point of Sale’s 2026 retailer guide, so the markup is the negotiable part.
Read in the full FAQ- What is tiered pricing in credit card processing?
Tiered pricing sorts transactions into buckets, commonly labeled qualified, mid-qualified, and non-qualified, each with its own rate. The processor decides which bucket a transaction falls into, which makes statements harder to check. Merchants on tiered plans can find their effective rate is above the qualified rate they were quoted, so calculating total fees divided by total volume is worthwhile.
Read in the full FAQ- Which credit card processing companies should a small online store compare?
Compare credit card processing companies on effective rate for your actual card mix, compatibility with your existing checkout, pricing clarity, and security compliance. This guide does not rank individual processor brands, because it only states facts it can support. It does compare processing approaches, including Avendo’s multi-processor routing, on the compare page, using the same criteria for each.
Read in the full FAQ- When is a single processor a better fit than routing?
A single processor can be the better fit when your store depends on a specific feature or integration only that provider offers, or when you already hold a negotiated rate you are happy with and want the simplest possible setup. For stores focused mainly on lowering card costs, per-transaction routing across several processors is worth evaluating alongside it.
Read in the full FAQ