Payment Logic - The last Software you need to code

Payment Logic – The last Software you need to code

Posted on by Toma Velev

Implementing the Payment Logic is the final piece in the software puzzle, completing the cycle of business operations that is required, must be and imposible to live without. If you don’t get payed – whatever you do – you at soem point stop. And nowadays everything could be packaged and made into product or service.

Payment Logic

Payments should be secure and well tested. They should be fast and user friendly. But, as a Developer or Architect, you need to implement the following steps.

  1. Mesmorize the user – offering him some product or service in exchange of some money.
  2. Offer payment gateways or integrations. More on this topic in a previous post: https://programtom.com/dev/2023/09/26/payment-integrations-different-ways-to-make-money/
  3. After the customer is willing to pay /has clicked the button) – create invoice/transaction.
  4. An ID of this record is passed to the payment gateway – along side an amount of some currency.
  5. The user must authorise money transfer.
  6. If you have served the offer from your own server
    1. you need to wait the payment gateway to push to your server – server to server transaction confirmation. 
    2. Some payment providers “buy now” buttons that execute handle the payment confirmation internally so the user is directly redirected to the success. But, even if handled internally – there is probably some async operations and calls. 

The whole logic is server to server calls that needs to be logged, traced and verified.

  • to your servers,
  • to payment gateways (paypal, google, apple pay, crypto or card gateways).
  • banks/credit/debit card processers
  • security filters (like captcha)

Many of the calls are asynchronious. I myself experienced this on the mobile side

When coding payment logic, several essential aspects come into play.

Transaction Security

Implementing encryption protocols and secure channels to protect sensitive payment data, such as credit card information, bitcoin addresses, invoices and so on – from unauthorized access or cyber threats. You could increase security by using

  • HTTPS, RSA Encryption in the database
  • Hashing of information that is only verified postfactum and not needed for additional logic.

Payment Gateway Integration

Integrate different payment gateways to give users more choices. This will facilitate seamless online transactions, allowing customers to securely submit payments using various methods like credit cards, digital wallets, crypto coints or bank transfers without you doing it yourself. This is what all start-ups do to get to the point of getting money and not wasting time on the highway. Read my book about startup steps: https://programtom.com/dev/product/the-start-up-ultimate-xx-steps-pdf/. It has Integration with Google Pay, PayPal and Coin Payments.

Error Handling

Implementing error-handling mechanisms to address payment failures, declined transactions, or other issues encountered during the payment process, providing users with clear feedback and guidance. You don’t want to make the money lost in the middle (taken from the users) and not received in your accounts. Implementing Atomic Transactions is a must and also complex in the multi-step flow of payments.

Payment Notifications

Setting up notifications to inform both users and administrators about the status of payment transactions, including successful payments, pending authorizations, or failed transactions, to maintain transparency and keep stakeholders informed. You could implement Push Notifications or use some Email Sending Micro Service like the one I’ve developed.