An Application Load Balancer (ALB) is a network component that operates at Layer 7 (application layer) of the OSI model, intelligently distributing incoming HTTP and HTTPS traffic across multiple backend servers, containers, or IP addresses. Unlike basic load balancers, an ALB performs content-based routing, directing requests based on specific criteria such as URL paths, host headers, or query parameters, which enables sophisticated traffic management and optimal resource utilization.

From a cybersecurity perspective, ALBs serve as critical security controls by centralizing SSL/TLS termination, offloading encryption processing from backend servers, and providing a strategic enforcement point for security policies. They commonly integrate with Web Application Firewalls (WAFs) to inspect and filter malicious traffic before it reaches application infrastructure. By continuously monitoring target health and routing traffic only to responsive instances, ALBs significantly enhance application availability, resilience, and overall security posture within cloud environments.