Difference Between IMAP and POP3

Edited by Diffzy | Updated on: April 30, 2023


Difference Between IMAP and POP3

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The SMTP protocol is mostly used in the first and second stages of the mail delivery system (see diagram above). Nonetheless, because SMTP is essentially a push protocol, it pushes the message data from the customer (client-side) to the server host that is required, it is not found in the third stage.

The method (direction of movement) associated with bulk data (a stream of data messages) is from the client to the relevant destination server, in simple terms. The third stage, on the other hand, requires a pull protocol, in which the client polls the server-side messages (retrieval of mail messages).

The regular flow of data from the server to the individual host device is from the server-side (client). As a result, an MAA (message access agent) is used in the third step.

The following are the two message access agents that are available:

  • Post office protocol, version 3 (POP 3)
  • Internet mail access protocol (IMAP 4)

The Post Office Protocol (commonly known as POP3) is a simple protocol with limited capabilities. The customer (client) POP3 software is installed first on the receiving PC, and then the host (server) POP3 software is installed on the mail server (POP3 is made of both the software i.e. client POP3 plus the server POP3).

When an individual user (client) is required to download an e-mail from the mail server's mailbox, mail access begins with the client. In this scenario, the events unfolded in the following order:

TCP slot 110 is used by the host server.

The client will then provide the server with its user name and password to gain access to the mailbox.

(For example, Gmail login) The user can now access his or her mailbox after successful authentication. Finally, the user can list and recover the individual mail messages one by one.

The Internet Mail Access Protocol (pull protocol), version 4, is another mail access protocol (IMAP4). POP3 and IMAP4 are extremely similar, although IMAP4 usually provides a lot more functions. IMAP4 is a significantly more sophisticated and complex protocol. This is perfect for people who use numerous computers, such as laptops at work and PCs at home.

Finally, before downloading the message, the user can scan for the email header. IMAP, in essence, creates a central repository that can be accessed from any computer.

As a result, email is not copied to the user's personal computer. Any e-mail may be partially downloaded by a user. This is especially useful if your connection is low and your e-mail contains multimedia that requires a lot of processing power.

POP3 and IMAP are both Message Accessing Agents that are commonly used to retrieve messages from a mail server and deliver them to recipient computers. Both aid in the configuration of SPAM and malware filters.


The email protocols POP3 and IMAP are commonly used to access emails from a third-party email client or software. On the internet, these are the most widely used Email Protocols. Both of these protocols make it possible to connect to the mail server using the email client that you used to create your email account. To set up our email account, we can choose any of them. POP3 and IMAP, like Simple Mail Transfer Protocol (SMTP), have particular functions and functioning principles. Let's take a closer look at POP3 and IMAP, as well as the distinctions between them.

If you'll be accessing your email from several devices, such as a work PC and a smartphone, IMAP is the way to go. If you only have one device and a high amount of emails, POP3 is the way to go. It's also more convenient if you have a slow internet connection and need to check your emails without going online. IMAP is more likely to meet the demands of the majority of individuals.

Note: If emails start vanishing from your inbox without being deleted, it's nearly likely because one of your devices is set to POP3. The problem can be resolved by backing up the emails and then resetting the email account to IMAP.

POP3 transfers email from a server to a specific machine before deleting it from the server.

IMAP, on the other hand, saves the message to a server and syncs it across various devices.

Difference Between IMAP and POP3 in Tabular form

Specifications POP3 IMAP
Meaning POP is a straightforward protocol that allows you to download messages from your Inbox to your computer. IMAP is a more advanced protocol that allows you to see all of the folders on the mail server.
Port  Ports POP3 and POP with SSL listen on port 110, while POP3DS listens on port 995. IMAP listens on port 143, IMAP with SSL on port 143, and IMAPDS on port 993.
Device access POP3 allows just one device at a time to access the messages.  IMAP allows numerous devices to access the mail at the same time.
Download POP3 mail must first be downloaded before it can be read. In IMAP, messages can be read in part before being downloaded completely.
Mail organize POP3 cannot be used to organise emails on a mail server.  IMAP is a protocol that allows you to organise your emails on a mail server.
Update mail POP3 cannot be used to generate, update, or remove emails on a mail server. IMAP allows you to create, update, and remove messages on your mail server.
Search content POP3 cannot be used to search for mail content on a mail server. To search, you must first download your email. MAP allows you to search the contents of your emails on your mail server.
Change A mail can be modified using local email software.  A web interface or email programme can be used to update a message.
Download All of the messages are downloaded at the same time. Before downloading a message, the header of the message can be viewed.

What is POP3? 

The most widely used protocol for receiving email over the internet is Post Office Protocol 3, or POP3. This standard protocol is used to receive emails from a remote server and send them to a local client. It is supported by most email servers and clients.

POP3 is a one-way client-server protocol for receiving and storing email on a server. The "3" refers to the original POP protocol's third version.

POP3 allows a recipient or their email client to download mail from the server regularly. As a result, POP3 allows a client to download an email from a server so that the receiver can view it offline. POP3 is similar to a "store-and-forward" service.

POP3 deletes the email from the server once it is on the client. Users or an administrator can choose that email is kept for a certain length of time in some implementations, allowing users to download email as many times as they like during that time frame.

Most common email applications, including Microsoft Outlook, support POP3. The protocol will operate if the email program is set up to accept POP3 connections. Each POP3 mail server has a unique address that must be entered into the email program for the protocol to connect. To receive the email, users must additionally enter their login and password.

Users can also check their email without an email program because POP3 is embedded into typical internet browsers like Internet Explorer and Mozilla Thunderbird.

By default, POP3 uses the following two ports:

  • Port 110 is the normal, non-encrypted port, 
  • while port 995 should be used when the user wishes to connect securely via POP3.

On TCP port 110, the server launches the POP3 service. When a client wants to retrieve email using POP3, it sets up a TCP connection with the server host. The POP3 server delivers a greeting after the connection is established. The session enters the authorization state at this moment.

The client and server exchange commands and responses in the transaction state until the connection is either closed or aborted.

Client commands are made up of case-insensitive keywords that may be followed by parameters. The server's responses include a status indicator and a keyword, which may be followed by other information.

The session enters the update state when the client issues the quit command. The POP3 server releases any resources gained during the transaction state and closes the TCP connection by saying "goodbye."

The POP3 server deletes the message when the POP3 session enters the update state.

Although POP3 has seen numerous improvements since its inception in the late 1980s, it remains popular due to its simplicity. Another reason for its widespread use is that it allows email to be retrieved quickly and with few errors.

When users need to view their email offline and use a specific device for recovery, the protocol is ideal. POP3 can also be used to send and store large amounts of email.

Because email is designed to be downloaded to the client and subsequently removed from the server, POP3 does not permit email alteration or synchronization on the server. The more advanced and complex Internet Message Access Protocol (IMAP) is employed in these scenarios.

IMAP may also poll an existing connection for new messages, and it can handle numerous server folders. These features are not available in POP3.

What is IMAP? 

If you've ever set up an email account, you've probably been asked whether you want to use POP or IMAP as your email protocol. This question can be completely perplexing to the inexperienced. However, the option you choose will have a significant impact on how you send, receive, and otherwise use email messages. While POP (Post Office Protocol) was once the most used email protocol, most people now prefer IMAP (Internet Message Access Protocol). Learn more about IMAP, including what it is, how it works, how it compares to POP, and its primary benefits, in the sections below.

IMAP, as the name implies, allows you to access your email messages from anywhere; it is typically accessed via the Internet. Email communications are kept on servers in the most basic sense. Your email client connects to the server every time you check your inbox to link you to your mails. When you read an email message using IMAP, you are reading it from the server rather than downloading or saving it on your computer. As a consequence, you may check your email from a variety of devices without missing a beat.

Think about IMAP as a middleman between your email client and your email server to get a better understanding of how it works. When sending and receiving email messages, email servers are always used. However, until you expressly delete them from IMAP, they stay on the server. When you sign into an email client like Microsoft Outlook, it uses IMAP to communicate with the email server. All of your email messages' headers are then shown. When you choose to read a message, it is downloaded fast so you can see if - emails are not downloaded unless you need to open them.

Assume again if you think IMAP and POP are interchangeable. POP communicates with your email server and downloads all of your new messages. They vanish from the server once they've been downloaded. If you check your email on a different device, you won't be able to see any of the messages you've already downloaded. POP is acceptable for those who only check their email from one device; however, those who travel or need to access their email from multiple devices will benefit greatly from an IMAP-based email service.

IMAP, unlike POP, allows you to access, organize, read, and sort your emails without having to first download them. As a result, IMAP is extremely quick and effective. The server also keeps track of all of the messages you send, allowing you to retrieve them from any location. IMAP does not transfer messages from the server to your computer; instead, it synchronizes your computer's email with the server's email.

Using IMAP has several advantages. To begin with, it allows you to access your email messages from any location and on as many devices as you choose. Second, a message is only downloaded when you click on it. As a result, you won't have to wait for the server to download all of your new messages before you can view them. Third, IMAP does not automatically download attachments. As a result, you can check your messages much faster and have more control over which attachments are accessed. Finally, IMAP can be utilized offline in the same way that POP can, so you can have the best of both worlds.

IMAP is growing increasingly popular as the globe gets more mobile than ever. With the rise of smartphones, laptops, tablets, and other devices, IMAP is in higher demand than ever. While POP will continue to be popular among individuals who only use one or two devices to check their email – as well as those who have slow Internet connections - IMAP will undoubtedly remain the protocol of choice for the majority of today's busy people.

Main Differences Between IMAP and POP3 in Points

  • IMAP is a sophisticated protocol that allows a user to browse all of the mail server's folders and retrieve messages. In comparison to IMAP, POP is a simple protocol that is just utilized to download messages from our inbox to our local computer.
  • IMAPDS (IMAP with SSL) listens on port 993, while it listens on port 143. POP3DS (POP3 with SSL) listens on port 995, whereas it listens on port 110.
  • Messages can be accessed from a variety of devices using IMAP. When utilizing POP3, you can only access your mail from one device at a time.
  • Before finishing the download, we can read the message in part. Only once the message has been downloaded can we read it.
  • Email software or a web interface can be used to update an IMAP account. The local email program can be used to update POP3 mail.
  • IMAP allows users to create, delete, and update mailboxes on the mail server, as well as establish a folder structure of mailboxes. The user cannot create, delete, or edit mailboxes on the mail server using POP3.


According to the information above, IMAP is more powerful, and it is ideal to utilize it if we want to view our emails from multiple devices, such as smartphones and PCs. POP3, on the other hand, is appropriate when we only use one device to access emails, have a significant quantity of emails, and want to access those emails offline.

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"Difference Between IMAP and POP3." Diffzy.com, 2024. Sat. 02 Mar. 2024. <https://www.diffzy.com/article/difference-between-imap-and-pop3-216>.

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