- Operates at the application layer (HTTP/HTTPS).
- Makes routing decisions based on URL, headers, cookies, or request content.
- Can direct traffic to specific servers based on paths (e.g.,
/api,/login). - Enables smart routing, A/B testing, and microservices routing.
- Supports features like SSL termination, caching, compression.
- Slower than Layer 4 but more flexible and aware of the application logic.
- Tools: NGINX, HAProxy, Traefik, AWS ALB.