SMTP VS POP3 – The Difference (+Pros & Cons)

SMTP VS POP3 – The Difference (+Pros & Cons)

Email continues to rule the business world as the best communication channel. As emailing is a part of every salesperson’s life, it is good to gather as much knowledge as you can about it. Since you actively use email, you must have come across a few protocols used for sending and receiving emails. They are SMTP, IMAP and POP3. If you haven’t, here’s an opportunity to fine-tune your knowledge. Here we shall discuss SMTP vs POP3 alone. If you wish to get a detailed comparison between SMTP VS IMAP and POP3, click here. Before we get started, it would be helpful if we look at what an email protocol is.

Table Of Contents

What Is An Email Protocol?

Email protocols refer to rules that enable transmitting email to and from the server. It essentially facilitates communication between a sender and recipient. There are two types of email protocols, namely inbound and outbound. IMAP VS POP3 falls in the inbound category as they help recipients see the emails others sent to their inboxes. SMTP is an outbound email protocol that helps relay messages to recipients. 

How Do Email Protocols Work?

Following is how the email protocols work.

When a sender sends an email, it reaches the email client-server with the help of SMTP. With the help of the same protocol, it is possible to transfer the message to the email client-server of the recipient. The email then hits the recipient’s inbox with the help of POP3 and IMAP. 

The most commonly used email protocols are SMTP, POP3 and IMAP. While SMTP is used to send emails, the other two protocols help receive emails. 

What Is SMTP?

SMTP stands for Simple Mail Transfer Protocol, which sends emails. The protocol has been around for the last 4 decades, and it works in synchronization with MTA (Message Transfer Agent) to send emails to their intended destinations. 

Though SMTP plays a major role in sending emails, it also filters the emails that pass through it. It helps limit the number of messages that the account can send within a particular period. 

Also, The SMTP ports include 25, 465 and 587. Out of these, port 25 is the default SMTP port. 

Pros And Cons Of SMTP

Following is a list of the advantages and drawbacks of SMTP


1. The protocol is quite reliable and predictable as it is very simple. 

2. With SMTP, there is no compatibility issue, therefore it is a universally adopted protocol.


1. When you use SMTP, there is always a security concern

2. Email messages that are too long get rejected by SMTP servers. 

3. Also, as it is too simple by nature, the protocol’s utility is limited. 

What Is POP3?

POP3 is Post Office Protocol version 3. It is a simple protocol that retrieves emails from a remote server into the recipient’s inbox. The first version of this protocol came in 1984, and it is popular as it is also quite easy to use and maintain. 

This protocol downloads a copy of the email from the server to the local device. As soon as that is done, the original data from the server’s inbox gets deleted. POP3 is useful for those who use only one device to access their email and read their messages when there is no internet connection. It also helps in freeing up inbox space as well. However, POP3 can’t sync the offline email with its online version. The chances are that when you lose your device or if it gets damaged, you will lose all the emails saved on it. 

The default port used by POP3 is 110 or 995.

Pros And Cons Of POP3

Following are the advantages and disadvantages of POP3


1. The biggest benefit of using POP3 is that the emails get downloaded to the recipient’s device, enabling you to view messages even when there is no active internet connection. 

2. It is also easy to open attachments as they get saved on the device.

3. There is the need for lesser storage space on the server as all emails get stored on the local device.

4. The process of configuring it is simple.


1. You can’t access your emails from multiple devices.

2. There is a chance of email folders getting corrupted, which can also make you lose the emails in one go.

3. Also, There can be viruses in email attachments that can affect your device. 

SMTP vs POP3  – What Are The Differences?

SMTP VS POP3 - Infographic

Following are the differences between both protocols

Abbreviation and other names

SMTP stands for Simple Mail Transfer Protocol and is also called PUSH protocol. POP3 is an abbreviation for Post Office Protocol version 3 and is also called a POP protocol. 

What it does

SMTP is used for sending emails, whereas POP3 is used to retrieve the emails.


SMTP transfers email from the sender’s device to the mailbox on the recipient’s server. It is an MTA (Message Transfer Agent).

POP3 retrieves emails from the mailbox on the recipient’s server to their device. It is an MAA (Message Access Agent). 

Number of MTAs and MAAs

SMTP has two MTAs, and POP3 has two MAAs.  

Port used

The SMTP port numbers are 25, 465 and 587 (25 being the default SMTP port), while that of POP3 is 110 or 995.


By now, you must have understood the main differences between SMTP and POP3 and what functions they perform. Both are the most widely used email protocols to date. There is IMAP as well, and you can find what makes it different from SMTP and POP3 here in these blogs – The difference between IMAP and POP3, the Difference between SMTP and IMAP.  

Try Salesblink For Free

Get better results for your sales effort with automated sales outreach