Payments, explained

The Acquirer

The merchant's bank in a card payment. It signs up the business, routes each sale for approval, settles the money into the merchant's account - and owns the risk when things go wrong.

Cardholder
Pays with a card
Merchant
Accepts the card
Acquirer
Routes & settles
Card network
Visa · MC · Amex
Issuer
Approves & pays

Cardholder, merchant, network, issuer - the acquirer is the only one working for the merchant.

Gateway - the pipe

Encrypts the transaction at checkout and routes it to a processor or acquirer. A gateway doesn't hold merchant funds or take on settlement risk - it's connectivity, not banking.

Common gateways
Authorize.netCybersourceNMI

Processor - the engine

Runs the authorization and settlement logic on the acquiring bank's behalf. Often the same company as the acquirer, or a close technology partner operating under its license.

Major processors
FiservGlobal PaymentsWorldpay (FIS)

PSP - the bundle

Wraps gateway, processing, and often the acquiring relationship itself into one product, so a merchant can start accepting cards without negotiating its own bank relationship. Some PSPs hold their own acquiring license and run full-stack; others partner with a bank acquirer behind the scenes.

Full-stack (own acquiring license)
AdyenStripeCheckout.com
Bank-partnered
SquarePayPal / Braintree

The merchant sees one bill - but underneath it, gateway, processor, acquirer, and network are frequently four separate companies, or one company wearing four hats.

Locked at the terminal

Card data is locked at the terminal (P2PE) and swapped for a token. The real number is only unlocked inside the acquirer's secure vault - a hardware security module no person can read from.

4929 •••• •••• 1234 → 🔒 encrypted in transit → tkn_9F2A…

Local acquiring, local outcome

A local acquirer processes the sale inside the customer's market instead of routing it abroad. The transaction looks domestic to the issuer - so it clears more cleanly.

  • Higher approval rates on in-market sales
  • Lower cross-border network fees
  • Settles & reports in local currency
A $100 card sale - proportions illustrative
Interchange
Interchange- paid to the card's issuer (largest slice)
Assessments- paid to the network
Markup- what the acquirer keeps
Settles funds in T+1 to T+2 days
Owns the chargeback & fraud risk

Of five parties in a card sale, the acquirer is the only one whose job is to get the merchant paid.

The line between "PSP" and "acquirer" is dissolving - the companies that control the full stack are the ones setting the economics.

If you're navigating where your business fits in the payments chain, I'd welcome the conversation.

Get in touch
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Educational use only; not affiliated with any card network or acquirer. Fee proportions are illustrative and vary by card type, region, and pricing model. June 2026