Card Networks, Issuers, and Acquirers Explained
Card networks such as Visa and Mastercard provide the infrastructure rails over which transactions travel. They set the rules for card issuance, merchant acceptance, interchange fees, and transaction routing. Crucially, they do not issue cards to consumers or maintain merchant accounts. They operate the highway; the banks operate the vehicles. Revenue comes from scheme fees charged on every transaction that passes through the network, typically running between 0.11% and 0.15% per transaction.
Issuing banks sit on the consumer side. They provide payment cards, maintain cardholder accounts, approve or decline transactions in real time, set credit limits, manage billing and disputes, and fund loyalty and rewards programmes. When funds finally settle, the issuer pays the acquirer and absorbs any fraud losses if rules were followed. Chase, Bank of America, Capital One, Barclays, and HSBC rank among the world's largest issuers. Their primary revenue source is the interchange fee collected on every purchase.
Acquiring banks represent the merchant side. They provide the merchant account that enables a business to accept card payments, facilitate the authorisation and settlement process, and assume risk related to chargebacks and potential merchant insolvency. Acquirers bear some liability for chargebacks and ensure funds reach the merchant after fees are subtracted. Major acquirers include Worldpay, Chase Paymentech, and Elavon. Increasingly, companies like Adyen and Stripe have built their own acquiring capabilities, allowing them to manage the full transaction lifecycle without relying on a third party bank.
Payment Processors, Gateways, and PSPs
Payment processors act as the operational bridge. They manage the technical flow of data between merchants, acquirers, and networks, handling authorization requests and batch submissions for clearing. They receive transaction data from merchants, format and route authorisation requests to the correct card network, relay approval or decline responses, and manage the batch settlement process. Major processors include FIS/Worldpay, Fiserv/First Data, and Global Payments. Many large processors also offer acquiring services, blurring the lines in practice.
A payment gateway is the technology layer that captures and encrypts payment data at the moment of sale, whether that happens online or at a physical terminal. The gateway does not move money. It moves information. Authorize.net, Braintree, and Stripe's gateway layer are well known examples. Modern providers increasingly bundle gateway functionality into their broader offering, which blurs the distinction between gateway and processor.
A Payment Service Provider, or PSP, wraps all of these functions into a single integrated service. Merchants working with a PSP do not need separate relationships with an acquirer, a processor, and a gateway. The PSP handles everything from authorisation through settlement. PSPs simplify onboarding and integration, especially for online and mobile businesses that do not want separate relationships with banks and networks. The PSP market was valued at approximately USD 87 billion in 2025 and is projected to reach USD 141 billion by 2034.
Payment Orchestrators: The Newest Layer
Payment orchestrators represent the newest layer in the payments ecosystem in 2026. These platforms connect merchants to multiple PSPs, acquirers, and local payment methods through a single integration. They handle intelligent routing, retries, fraud tool stacking, and failover so businesses can optimize approval rates and costs without building dozens of separate connections.
For each transaction, an orchestrator evaluates the card's issuer, geography, payment method, historical performance data, and cost to select the optimal route. If the primary route declines, the orchestrator automatically cascades the transaction to a secondary or tertiary provider. Spreedly, Payrails, Primer, IXOPAY, and Gr4vy are among the leading platforms in this space.
Payment Facilitators vs. Independent Sales Organisations
Payment Facilitators, commonly known as PayFacs, represent one of the most important structural innovations in the modern payments industry. A PayFac holds a master merchant account with an acquiring bank and onboards individual businesses as sub merchants under that umbrella. This allows for dramatically faster onboarding, often in minutes rather than weeks, because the PayFac conducts its own underwriting rather than relying on the bank to process each application. Stripe, PayPal, and Square are the most prominent examples of the PayFac model. The structural trade off of this approach, including frozen funds and sudden terminations, is well documented.
The trade off is liability. PayFacs assume full responsibility for chargebacks, fraud, and regulatory compliance across their entire sub merchant portfolio. They must maintain robust PCI DSS, KYC, and AML programmes to manage this exposure. The model has become increasingly dominant over the Independent Sales Organisation (ISO) model, which operates differently.
An ISO functions as a third party reseller of merchant accounts. ISOs establish relationships with acquiring banks and processors, then connect merchants to those services. They do not hold master accounts and do not directly handle funds. The merchant contracts with the processor, and the ISO earns a commission. While ISOs are gradually losing ground to PayFacs, they remain relevant for merchants that need highly customised solutions or operate in specialised industries.
Choosing the Right Partners
Each player takes a small cut of every transaction, and the way they interact determines speed, cost, and reliability. A merchant using a single PSP may enjoy simplicity but miss optimization opportunities that orchestrators unlock. Larger enterprises often combine direct acquirer relationships with orchestration to maintain control while gaining flexibility. Understanding each role helps businesses select the right partners and avoid costly mismatches that erode margins or introduce unnecessary points of failure.