Card Payment

This document details the sequence of API calls required to pay card dues

This API is required to enable issuers to collect and settle cardholder dues on credit cards through digital channels such as mobile and web applications.

Credit card customers must be able to pay their outstanding balances (minimum due, full due, or a specific amount) directly from a linked debit or funding account. This API provides a secure and standardized mechanism to initiate and process these payments in real time.

This flow applies to credit card payment, and provides a visual sequence diagram that explains the Card Payment user journey end-to-end—from the mobile/issuer app UI actions, through the issuer middleware, to the Network APIs—and back with the final response.

Card Top-Up/Payment

User

Issuer App

Issuer Middleware

Network

Functional flow explained

1. Authentication
   1. User → Issuer App: Login
      The user logs in to the issuer application.
2. Retrieve available cards
   1. Issuer App → Issuer Middleware: Get list of cards
      The app requests the user’s card list from the issuer backend.
   2. Issuer Middleware → Network: GET /cards/search
      Middleware calls the Network API to search and retrieve cards.
   3. Network → Issuer Middleware: HTTP 200 response
      Network returns a successful response with card data.
   4. Issuer Middleware → Issuer App: Forward response
      Middleware passes the response back to the app.
   5. Issuer App → User: Show user list of cards
      The app displays the returned cards for user selection.
3. Initiate Payment
   1. User → Issuer App:
      The user performs the following steps in the app:
      1. Select a card
      2. Make a payment
      3. Select the debit account to fund the transaction
   2. Issuer App → Issuer Middleware: Forward request
      The app sends the selected card + amount + funding account information to middleware.
   3. Issuer Middleware (internal step): Debit cardholder account
      Middleware performs/initiates the debit from the selected funding account
   4. Call payment API
   5. Issuer Middleware → Network: POST /cards/{id}/payment
      Middleware calls the Network payment endpoint for the selected card {id}.
   6. Network → Issuer Middleware: HTTP 200 response
      Network returns a success response
   7. Issuer Middleware → Issuer App: Forward response
      Middleware forwards the result to the app.
   8. Issuer App → User: Forward response (display outcome)
      The app presents the transaction outcome to the user (success/failure details).