API Gateways and Edge Architecture Explained

When an application is split into multiple services—such as authentication, orders, and payments—each running on its own host and port, handling client requests becomes challenging. Teams must decide how to distribute URLs, validate tokens, prevent brute-force attacks on login endpoints, manage CORS headers, and cache expensive responses without duplicating code across every service.

The standard solution for this complexity is an API gateway. It acts as a reverse proxy sitting between the public internet and private backend services, handling routing, authentication, rate limiting, and caching. To use an analogy, a hotel front desk acts like an API gateway, preventing guests from wandering directly into staff areas and managing requests centrally.

The network architecture places the WAF and CDN at the edge, followed by the API gateway, while backend services remain safely on a private network. Configuration is typically declarative, defining routes, JWT authentication requirements, per-client rate limits such as 100 requests per minute, response caching rules, and header transformations.