What approaches and tools do you know for organizing the gateway role in system architecture?

The role of an API Gateway in system architecture is to centrally handle incoming requests, route them, authenticate, aggregate, and perform other functions. Main approaches and tools:

• Using specialized API Gateways: such as Kong, Zuul, NGINX, AWS API Gateway. They provide routing, load balancing, caching, rate limiting, and security.
• Implementing your own gateway in Java: using Spring Cloud Gateway or Netflix Zuul. Allows flexible configuration of request processing logic.
• Gateway functions: authentication and authorization, request and response transformation, aggregation of multiple services, logging, and monitoring.

Example of a simple router on Spring Cloud Gateway:

@Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
    return builder.routes()
        .route("path_route", r -> r.path("/api/**")
            .uri("http://backend-service"))
        .build();
}

Choice of approach depends on scalability, security, and complexity requirements.