Payment System: High-Level Design

Step 4: High-Level System Design

Architecture Overview

The design is a set of services around one core Payment Service. Before we draw the diagram, we name each part and what it does.

API Gateway / load balancer. This is the entry point for every request. It handles authentication, rate limiting, and routing to the internal services.

Payment Service. This is the core backend service that holds the payment logic. We could split it into several microservices later, but for now we treat it as one logical unit. It orchestrates each payment request from start to finish