2 April 2026

How Payment Processing Works: A Complete Guide

How card payments are processed from authorisation to settlement. Understand processors, gateways, interchange fees, and the complete transaction lifecycle.

Payment processing is the system that moves money from a customer's card to a merchant's bank account. This guide explains every step, the companies involved, and how costs are determined.

The Payment Processing Chain

Every card transaction involves five parties:

  1. Cardholder — the customer paying
  2. Card issuer — the bank that issued the card
  3. Card scheme — the network (Visa, Mastercard, etc.)
  4. Acquiring bank — the merchant's bank
  5. Merchant — the business accepting payment

Step by Step: How a Transaction Works

1. Authorisation

The payment gateway captures card details and sends them through the payment processor to the card network and issuing bank. The bank checks the card is valid, has sufficient funds, and passes fraud checks. This takes 1-3 seconds.

2. Capture

The merchant confirms they want to collect the authorised funds. This may happen immediately or later (e.g., when goods are shipped).

3. Clearing

Transaction details are exchanged between the acquiring and issuing banks through the card network to determine final amounts.

4. Settlement

Funds are transferred from the issuing bank through the card network to the acquiring bank, then into the merchant's merchant account. This typically takes 1-3 business days.

Understanding Fees

The Merchant Discount Rate includes:

  • Interchange fees — paid to the issuing bank (0.2-0.3% for UK consumer cards)
  • Scheme fees — paid to Visa/Mastercard
  • Acquirer markup — the acquiring bank's profit

Types of Payment Providers

Phone Payment Processing

Phone payments follow the same processing chain but require additional security. DTMF suppression captures card details securely before they enter the standard processing flow. Contact Paytia to learn more.

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