Concept

Authorization is the step in a card payment where the customer’s bank checks if the transaction can go through.

When a customer taps, inserts, or enters their card details, the system asks a simple question:

“Is this transaction valid, and is there enough money or credit available?”

The issuing bank evaluates the request in real time and responds with either:

• Approved → the transaction can proceed
• Declined → the transaction is rejected

This decision typically takes 1–3 seconds.

Authorization does not move money.

It only confirms whether the payment is allowed.

Framework — The Authorization Chain

To understand authorization, use this simple flow:

Customer → Merchant → PSP/Gateway → Acquirer → Card Network → Issuer → Decision → Back to Merchant

Step-by-step:

1. Customer initiates payment
   (card tap, insert, or online entry)
2. Merchant sends request
   via a Payment Service Provider (PSP) or Gateway
3. Acquirer forwards request
   to the relevant card network (Visa, Mastercard, etc.)
4. Network routes to issuer
   (the customer’s bank)
5. Issuer evaluates transaction
   using checks such as:
   • Available funds or credit
   • Fraud signals
   • Card status (active, blocked, expired)
6. Issuer sends decision
   (approved or declined)
7. Response travels back
   to the merchant in real time

Example — Real SMB Scenario

A customer buys a £45 product from an online store.

• They enter their card details at checkout
• The store’s PSP (e.g., Stripe) sends the authorization request
• The customer’s bank checks:
  • Do they have at least £45 available?
  • Is this transaction normal behavior?
• The bank approves the payment

The merchant sees:

✅ “Payment Approved”

At this point:

• The funds are reserved, not yet received
• The order is confirmed
• Fulfilment begins

Impact — Why This Matters

Most SMBs misunderstand authorization—and this creates real problems.

1. Approval Rates Drive Revenue

If authorization fails:

• the customer cannot complete the purchase
• revenue is lost instantly

Even small improvements in approval rates can increase revenue materially.

2. Authorization ≠ Money Received

This is a critical distinction.

After approval:

• money is not yet in your account
• it must go through capture and settlement

Misunderstanding this leads to:

• false cashflow assumptions
• operational errors in fulfilment

3. Declines Are Not Always Final

Transactions fail for many reasons:

• insufficient funds
• suspected fraud
• incorrect data
• bank rules

Some declines can be recovered through:

• retries
• alternative payment methods
• improved checkout design