Part III: Cards: The Dominant Rail
Archive: extra
Now that you know the players, it's time to watch them in action. Starting with the fastest, most dramatic stage of the payment lifecycle: Authorization.
| Role | What They Do | Revenue Model | Who They Serve | Examples |
|---|---|---|---|---|
| Card Network | Provides rails, rules, branding, and dispute arbitration between issuers and acquirers | Network assessment fees (basis points per transaction, both sides) | Issuers and acquirers (two-sided market) | Visa, Mastercard, UnionPay |
| Issuer | Issues cards/credentials, extends credit, approves or declines transactions, bears fraud risk | Interchange + interest + annual fees | Cardholders (consumers and businesses) | Chase, HSBC, DBS, Capital One |
| Acquirer | Signs merchants, routes transactions to the network, settles funds to merchant accounts | Merchant discount rate (bundles interchange + network fees + margin) | Merchants | Worldpay, First Data, Elavon |
| Payment Gateway | Securely collects payment credentials (online or in-app) and transmits them to the acquirer | Per-transaction gateway fee (flat or basis points) | Merchants (especially e-commerce) | Braintree, Authorize.Net, Cybersource |
| PSP (Payment Service Provider) | Bundles gateway + acquiring + risk management into a single integration; often acts as payment facilitator | Blended rate per transaction (e.g., 2.9% + $0.30) | Merchants (SMB to enterprise) | Stripe, Adyen, Square, PayPal |
| Payment Orchestrator | Routes transactions across multiple PSPs, acquirers, and rails to optimize approval rates, cost, and redundancy | SaaS fee or per-transaction fee | Large merchants and platforms with multi-PSP setups | Spreedly, Primer, Gr4vy |
Table 5: The Payment Ecosystem Roles Matrix. Each role solves a different coordination problem. As you move down the table, each layer typically sits on top of the ones above it — an orchestrator routes through PSPs, which bundle gateways, which connect to acquirers, which plug into card networks. Understanding who does what prevents the common mistake of conflating a "payment processor" with a "payment gateway" or a "card network."