What is a port number?

A port number identifies a specific service on a host. Well-known ports (0-1023) include 80 (HTTP), 443 (HTTPS), 22 (SSH), and 53 (DNS).

A MIME (media) type labels the format of a file or HTTP body, like text/html, application/json, or image/png, so software knows how to handle it.

What is the difference between port 80 and 443?

Port 80 serves HTTP (unencrypted); port 443 serves HTTPS (TLS-encrypted). Modern sites use 443.

application/json. For JavaScript use text/javascript, and for plain text use text/plain.

Well-known ports are 0-1023, registered ports 1024-49151, and dynamic/ephemeral ports 49152-65535.

Reference

Common TCP/UDP port numbers and MIME content types. Click any card to copy the port or content type.