How to Accept Online Payments on Your Website: Cards & Installments

Accepting online payments on a website looks simple at first glance: a button, a card number, a confirmation. In reality there are three separate issues: technical integration, security and legal documents. This article walks through them in order.

How payment works

In a properly built system, card data never enters your website. The flow looks like this:

1. The user clicks the payment button on the site.
2. The site creates an order with the payment provider and redirects the user to the provider's (or the bank's) secure payment page.
3. The user enters card details only on that page and, if required, confirms with 3D Secure.
4. The provider reports the result to your site through a callback, and the user returns to a result page.
5. The site verifies the result, records the payment and gives the user a reference number.

This model frees your site from the burden of storing card data. Our payment portal is built on the same principle.

Security: what to watch for

• Card data must not be stored on your server. This sharply reduces both risk and compliance requirements.
• Confirm the result only from the provider's notification. You can't trust a "success" parameter that comes back through the user's browser, because it can be forged.
• Store amounts as whole numbers (for example, in the smallest currency unit). Calculating with decimal fractions leads to rounding errors.
• Be ready for repeated notifications. The provider may send the same notification several times; the same payment must not be recorded twice.
• Test in sandbox mode. Before trying a real card, run every scenario with the provider's test cards: successful, declined and abandoned payments.

Paying in installments

In Azerbaijan, installments are usually a product of the bank that issued the card. This means the approval of the installment, the number of months and any interest are set by the bank, not by the website. If the bank does not approve the installment, the user should be offered the option to pay in one go. The result can arrive late, so the system must handle the "pending" state properly and must not record it as a failed payment.

Don't forget the legal pages

Payment providers usually require separate pages on the website:

• Payment terms: accepted cards, currency, installments, security, the confirmation process.
• Refund terms: in which cases, within what period and by what method refunds are made, and how to submit a request.

These pages matter both for the provider's approval and for your customers' trust. For examples, see our payment terms and refund terms pages.

Conclusion

Online payment integration is more than adding a button: it means a correct flow, secure verification of the result and legal readiness. If you want to add payments to your site or have an existing setup reviewed, contact us or take a look at our web platforms service.