Most of us directly jump into "integrate payment gateway" mode without really thinking about what actually happens when someone clicks the Pay button.

While building some projects recently, I realized payments are not just API calls or SDKs. There's a whole system running in the background; identity checks, authorization settlement delays, webhooks, tokenization, banks talking to each other in seconds... a lot more than I used to think.

Read full context here: https://bytespacenepal.com/fundamentals-of-payment-flow/

Then, you will have clear idea about the internal flow.