| Functionality | Acts as an intermediary between clients and servers, handling requests and responses. It can also provide caching, SSL termination, and security features. | Distributes incoming traffic across multiple backend servers to improve performance, scalability, and reliability. It can also perform health checks on servers. |
| Use Case | Enhances web application security, performance, and scalability. Often used for content caching, load balancing, and protecting servers from direct exposure. | Ensures high availability, fault tolerance, and scalability of web applications, APIs, and services with high traffic volume. |
| Handling Requests | Receives client requests, forwards them to the appropriate backend server, and returns responses to clients. | Distributes incoming requests among a pool of backend servers based on predefined algorithms (e.g., round-robin, least connections). |
| Caching | Can cache static and dynamic content to reduce latency and server load, improving overall performance. | Typically does not perform caching, as its primary focus is on load distribution and ensuring server availability. |
| SSL Termination | Handles SSL/TLS encryption and decryption, offloading this task from backend servers and improving performance. | Can also perform SSL termination, reducing the computational overhead on backend servers and enhancing security by centrally managing certificates. |
| Security Features | Provides security features such as access control, rate limiting, and protection against DDoS attacks. | Offers basic security features like IP whitelisting and firewall rules, but may not be as robust as dedicated security solutions. |
| Deployment | Often deployed in front of web servers or application servers to improve performance and security. | Typically deployed in a network between clients and servers, ensuring that requests are evenly distributed and servers are not overloaded. |
| Examples | Apache HTTP Server, HAProxy | HAProxy, AWS Elastic Load Balancing, F5 BIG-IP |