Processor vs. network path: a payments teardown

Ask three payments vendors what they do and you will hear the same four words — gateway, processor, acquirer, network — used to mean whatever the pitch needs them to mean. That is not an accident: the distinctions are where the money and the leverage live. Every card payment touches at least four entities: an issuer, a card network, a processor, and an acquirer, each charging its own fee and carrying its own risk (Hyperswitch, 2026).

This is the teardown we walk growth-stage teams through, built from years untangling contracts signed before anyone read the markup line.

Who does what, in order

Logically, a card transaction moves through the stack in a fixed order, then comes back with an approval or a decline. The gateway captures and encrypts the transaction; the processor formats and transmits it; the card network routes it to the issuer; the issuer authorizes or declines — and the acquirer comes into play during clearing and settlement, not during the authorization round trip (payments practitioners, 2025).

• Issuer — the cardholder's bank. It approves or declines, funds the transaction, and collects interchange. It owns the customer relationship on the card side.
• Card network — Visa, Mastercard, Discover. It owns the rails, sets the interchange and assessment schedules, and routes authorization and clearing messages. It sets the wholesale price of moving money.
• Processor — the pipe that routes transactions from the merchant's checkout to the networks to the issuer and back. Examples include Fiserv, TSYS, Worldpay, and Elavon. It sets the retail price — its markup — and the service around it (PayRam, 2026).
• Acquirer — the licensed financial institution that holds the merchant account, settles the funds, and carries the underwriting and chargeback risk. One provider is often several of these at once, which is exactly why the terms get used interchangeably (Haipay, 2026).

Where the money goes

Your all-in card cost — the “effective rate” on your statement — is interchange plus network assessments plus processor markup plus per-transaction fees plus extras, divided by your total card sales (Clearly Payments, 2026). It resolves into three parts, and only one of them is yours to move.

1. Interchange (pass-through)

Interchange is the wholesale fee the cardholder's issuing bank deducts from every Visa or Mastercard transaction. It is set by the card brands, not your processor, and usually accounts for 70 to 90 percent of total card-fee spend (myPayAdvisor, 2026). It varies by card type and how the transaction is processed, so data quality matters.

2. Assessments (pass-through)

Assessments are what the card brand itself charges: roughly 0.13 to 0.15 percent of volume, plus small fixed per-transaction fees such as Visa's NABU and Mastercard's AANF at about $0.0195 each (Sleft Payments, 2026). Like interchange, no processor can negotiate this down for you.

3. Processor markup (negotiable)

The markup is what your processor charges on top, and it is the only negotiable line — it is where processors make their money. Under interchange-plus, you see every component; under a flat rate such as 2.6% + $0.10, the processor keeps the spread (Sleft Payments, 2026). Tiered pricing is worse: transactions get sorted into opaque buckets the processor defines, producing effective rates of 2.5 to 4.0 percent.

Direct processor vs. PayFac: two ways onto the rails

The other structural choice is how you get onto the path at all. A processor is the pipe that routes transactions; a payment facilitator (PayFac) is a front office that lets sub-merchants accept payments under its own master account, so they onboard in minutes instead of underwriting their own merchant account (PayRam, 2026). The two sit at different layers, make money differently, and one depends on the other.

• Direct processor / your own MID. More control over interchange optimization, routing, and economics; more underwriting, compliance, and reconciliation burden that lands on you. The right fit when volume and margin justify owning the relationship.
• PayFac / sub-merchant model. Fast onboarding and abstracted complexity, at the cost of the facilitator's blended pricing and the facilitator carrying — and pricing in — your risk. The right fit early, or when embedding payments into a platform where speed of activation is the product.

Neither is “better.” The mistake is choosing on onboarding speed alone and discovering, at scale, that the blended economics and the loss of routing control cost more than the merchant-account overhead you avoided.

Routing is a lever, not a given

Once you understand the network sets interchange and the processor moves the message, network routing becomes a cost lever. Debit transactions can often be routed across more than one network, and least-cost routing chooses the cheaper path per transaction — on top of a regulatory fight that is still unsettled. The Fed's Regulation II debit-interchange cap is under challenge at the Sixth Circuit in Linney's Pizza v. Federal Reserve, with no oral-argument date set, and the recently approved $38B Visa/Mastercard credit-interchange settlement includes a five-year interchange rollback (The Green Sheet, 2026). Your routing configuration decides how much of that you capture.

This is also a diligence issue

The same path you optimize for cost is the path your sponsor bank and its examiners inspect. A June 2, 2026 joint action by the Fed, FDIC, and OCC reissued 15 interagency guidance documents to strip out “reputation risk,” pushing supervision toward hard, demonstrable controls (OCC, 2026). A diligence-ready program can name who holds the merchant account, how settlement works, and how disputes are handled (FintechSpecs, 2026). If you cannot draw your own payment path, that is the gap diligence will find.

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