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Difference Between POP3 and IMAP

By SamK on March 06, 2024

POP3 (Post Office Protocol version 3) and IMAP (Internet Message Access Protocol) are two different protocols used for retrieving emails from a mail server. Here are the key differences between the two:

Email Retention:

POP3: POP3 is designed to download emails from the server to the email client (e.g., Outlook, Thunderbird). By default, POP3 removes the emails from the server once they are downloaded to the client, although some settings allow you to keep copies on the server.

IMAP: IMAP is designed to sync emails between the server and the email client. Emails are stored on the server, and changes made (such as deleting or moving emails) are reflected on both the server and the client.

Email Access:

POP3: With POP3, emails are downloaded to the client and can be accessed even without an internet connection. However, changes made to emails (such as read/unread status) on one device are not synced to other devices.

IMAP: IMAP requires an internet connection to access emails because emails are stored on the server. Changes made to emails are synced across all devices connected to the same IMAP account.

Storage Space:

POP3: Since emails are downloaded to the client and removed from the server (in most cases), POP3 requires less server storage space.

IMAP: IMAP requires more server storage space because emails are stored on the server and accessed by multiple devices.

Email Organization:

POP3: With POP3, emails are stored locally on the client, so organization (such as creating folders) is done on the client side.

IMAP: IMAP allows for better email organization because changes made (such as creating folders or moving emails) are synced across all devices.


Both POP3 and IMAP support secure connections (POP3S and IMAPS) to encrypt data between the client and the server, providing a secure way to retrieve emails.


In summary, POP3 is better suited for users who want to download emails to a single device and keep them offline, while IMAP is better suited for users who want to access emails from multiple devices and have changes synced across all devices.