In web technology, a server is a computer system that listens for requests from clients (browsers) and responds with data — HTML pages, images, JSON from an API, and so on. The word "server" can refer to the physical hardware, the operating system, or the software (web server application) running on that machine.
Types of Servers in Web Architecture
- Web Server — Handles HTTP/HTTPS requests and serves static files. Examples: Nginx, Apache, IIS.
- Application Server — Runs the backend application logic (ASP.NET Core, Node.js, Django). Processes dynamic requests, talks to databases.
- Database Server — Manages and serves database queries. Examples: SQL Server, PostgreSQL, MySQL.
- File Server — Stores and serves files over a network.
- Mail Server — Sends, receives and stores email.
Client–Server Model
The web operates on a client–server model. The client (browser) sends an HTTP request. The server processes it and sends back a response. This separation allows servers to serve millions of clients simultaneously.
Physical vs Virtual Servers
- Bare metal — A dedicated physical machine.
- Virtual Machine (VM) — Software-emulated server running on physical hardware.
- Container — A lightweight, portable unit (Docker) running on a shared OS kernel.