Difference Between SMTP and HTTP

Pre-requisites: SMTP, HTTP 

A network protocol is an accepted set of rules that govern data communication between different devices in the network. In this article, we will see the difference between SMTP and HTTP protocols. 

SMTP

SMTP (Simple Mail Transfer Protocol) is a protocol for managing Internet’s electronic mail. It is an application layer protocol. It uses TCP due to its reliable data transfer service. TCP establishes SMTP connections at port 25. SMTP uses persistent connections. The same TCP connection can be used to send multiple emails, once the connection has been established. Only 7-bit ASCII content is to be directly sent. Other content needs to be encoded to 7-bit ASCII and then decoded at the receiving end.

DNS uses distributed servers so that data remains distributed in places and per server load decreases. But SMTP never uses intermediate mail servers. Mail sent by user A to B will go directly from A’s server to B’s server, and nowhere in between.

HTTP

HTTP is a client-server protocol. It is IP based communication protocol that is used to deliver data from server to client or vice-versa. Any type of content can be exchanged as long as the server and client are compatible with it. 

Difference between SMTP and HTTP

SMTP	HTTP
SMTP is used for mail services.	HTTP is mainly used for data and file transfer.
It uses port 25.	It uses port 80.
It is primarily a push protocol.	It is primarily a pull protocol.
It imposes a 7-bit ASCII restriction on the content to be transferred.	It does not impose a 7-bit ASCII restriction. Can transfer multimedia, hyperlinks, etc.
SMTP transfers emails via Mail Servers.	HTTP transfers files between the Web server and the Web client.
SMTP is a persistent type of TCP connection.	It can use both Persistent and Non-persistent.
Uses base64 encoding for authentication.	Uses different methods of authentication such as basic, digest, and OAuth.
Does not support session management or cookies.	Supports session management and cookies to maintain state.
Has a smaller message size limit compared to HTTP.	Has a larger message size limit compared to SMTP.
Requires authentication for sending emails.	Does not require authentication for browsing web pages.
Supports both plain text and encrypted communication (SMTPS or STARTTLS).	Supports both plain text and encrypted communication (HTTPS).