Webserver

A web server is software that accepts HTTP requests from clients, such as web browsers, and returns HTTP responses containing resources like HTML pages, images, or other data. It primarily serves static content but may also generate dynamic content by invoking application code via interfaces such as CGI, FastCGI, or built-in modules.

When handling requests, the server listens on standard ports (typically 80 for HTTP and 443 for HTTPS), negotiates encryption with TLS for secure connections, and may implement virtual hosting to serve multiple domains from one server instance. Web servers can operate using different architectural models, including multi-process, multi-threaded, or event-driven asynchronous designs, to manage concurrent connections efficiently.

Popular web server programs include Apache HTTP Server, Nginx, Microsoft IIS, Caddy, and Lighttpd. They commonly offer features such as virtual hosting, URL rewriting, access control, compression, caching, and TLS termination. Many deployments also use the web server as a reverse proxy or load balancer to distribute traffic to application servers or microservices.

Although tightly integrated with the web stack, a web server is not the same as an application server; it may run static content directly but often interfaces with application frameworks and databases to deliver dynamic content. Proper configuration and security practices are essential to performance and safety.