Protocol (Internet)


A protocol is a set of rules to communicate over the Internet about something.


Like technology stack, protocols have a hierarchy. The lower ones handles basic data passage, while the higher ones specify communications for specific applications (eg: Email).


The basic protocols of communicating data over the Internet is TCP/IP or UDP. All machines involved in the Internet must follow these protocols to send and receive data.


Built on top of TCP/IP or UDP are protocols that communicate for certain applications. Examples are HTTP for webpages/APIs, SMTP for Emails, and SSH for secured shell.



Not just the Internet, many communication devices must have protocols to communicate:

  • Morse code.
  • Telephone routing.
  • TV signal transmission.
  • Bluetooth
  • RFID


  • HTTP (webpages, APIs)
  • SSH (remote shell login)
  • SMTP (mail)