Post Office Protocol (POP3)

Post Office Protocol version 3 (POP3) lets an email client retrieve messages from a mail server.

Format
Email & Communication
Updated
Updated
Glossary Email & Communication
Post Office Protocol Also known as POP3.Aliases: POP, mail download protocol.

Definition

Post Office Protocol version 3 (POP3) lets an email client retrieve messages from a mail server.

How it works

POP3 does one thing: connect, download the mail, and usually delete it from the server. That model made sense when people read email on a single computer, and it still suits keeping a local archive. Use more than one device, though, and the lack of synchronization shows quickly — which is why IMAP largely took over.

Example: A desktop mail client downloads messages from a POP3 mailbox into local storage.

Often confused: POP3 downloads mail to one place, IMAP keeps mail on the server and syncs every device, and SMTP handles the sending.

Sources

Last reviewed 2026-07-19.