What is IMAP?

Email protocols are vital, especially when setting up an email account. The selected protocol will have a major impact on users’ entire emailing experience — which is why understanding them and their features are essential.

POP and IMAP are the two commonly used protocols that enable users to send and receive emails. However, IMAP is the recommended protocol, especially for users that need to check their emails from multiple devices.

What exactly is IMAP?

IMAP (Internet Message Access Protocol) enables users to manage their emails on the email server directly. With IMAP, users do not have to download or store an email message before accessing it. Plus, it allows them to access their email from any location using any device.

IMAP only downloads a message or attachment when users click on it, thus speeding up the email retrieval process.

You can use IMAP to organize your messages into folders, flag them as read, and copy, delete, or forward them straight on the server.

IMAP doesn’t manage the contents of your inbox locally, so it needs constant internet connection to work.

How IMAP Works

IMAP works as an intermediary between the user’s email client and email server. Users use email servers to send and receive messages even though with IMAP, the messages remain on the server. When users sign in to an email client, it uses IMAP to contact the email server.

The IMAP protocol uses the TCP/IP transport layer for communication to ensure data delivery, and it uses two ports by default — Port 143 and Port 993.

Port 143 is an unencrypted IMAP port, while port 993 is secure.

Once the IMAP client establishes the TCP connection with the IMAP server, the server listens to the default port (port 143) to ensure email retrieval. Also, IMAP synchronizes all user devices with the main server.

Features of IMAP

  • Users can use IMAP to manage different mailboxes, and they can transfer messages between mailboxes.
  • IMAP allows users to organize their emails into different categories and folders.
  • Users can sync the folders across all their devices.
  • Users can access their mail from a remote device while keeping the mails on the server.
  • IMAP enables users to use message flags to keep track of messages they have read.
  • The server saves the email status, and users can view it on any device.
  • Users can view messages without downloading them, and they can delete messages directly on the server.
  • IMAP enables users to download a portion of their messages.
  • Users can organize their mails or rename their mailbox on the server.
  • The search feature enables users to search the contents of emails.
  • Users can view the email header, including the sender, subject, and date, before downloading.
  • IMAP allows users to create a mail hierarchy according to importance.

Advantages of IMAP

  • Users won’t lose their emails in cases of stolen devices, crashed computers, or accidental data deletion.
  • IMAP enables users to stay connected to the email server for as long as the user interface remains active, and they can download email content on demand.
  • IMAP allows different clients to connect to the same mailbox simultaneously, and it offers features to enable clients to detect changes made by other connected clients.
  • Users can access their email messages from anywhere in the world using multiple devices.
  • The IMAP protocol allows users to read their messages without having to download them.
  • Attachments are not downloaded automatically with IMAP.
  • Users can keep track of the state of their emails with ease using flags.
  • IMAP allows users to rename, delete and create mailboxes on the server, and they can move messages between mailboxes.
  • IMAP uses minimal local storage, and users can access it on the web without an email client.
  • Users can easily migrate with IMAP.

Disadvantages of IMAP

  • Internet hackers can easily breach the IMAP protocol authentication mechanism if an unencrypted connection is used.
  • It is mandatory to have an internet connection to read, reply, or search messages on IMAP.
  • Users may need to pay for more extensive mailbox storage on the server.
  • It is complex to maintain IMAP


IMAP and POP are the commonly used protocols for email retrieval. Unlike IMAP, where users do not need to download their messages from the server, POP downloads all new messages from the server for users. Plus, after the messages download, they disappear from the server.

Users cannot access all their messages from different devices using POP because the previously downloaded messages are no longer available on the server. POP is suitable for users who use a single device to check their emails. Still, for users that travel and need to access their email from multiple devices, the IMAP protocol is recommended.

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