What is a web server?#

A web server is a program, not a device. It runs on a server and listens for HTTP and HTTPS requests. When a browser asks for an address, the web server decides which file to hand back or which site code to run.

Example#

Suppose someone opens a WordPress article page:

  1. The web server receives the request.
  2. If it is a plain file, such as an image or CSS, it sends it directly.
  3. If the page is generated by PHP, it hands the job to PHP.
  4. It returns the resulting HTML to the browser along with a status code.

The best-known ones#

  • Apache: long-established, flexible, and popular on shared hosting thanks to the .htaccess file
  • Nginx: lightweight and fast at handling many simultaneous connections
  • LiteSpeed: an Apache-compatible web server often seen on WordPress hosting

Where you run into it#

  • Errors such as 404 and 500 are returned by the web server.
  • Redirects, compression and SSL certificates are usually configured in the web server.
  • Hosting support may ask whether your site runs on Apache or Nginx.

Difference from a server#

A server is the machine; a web server is the software on it that serves the site.