Everything You Need to Know About POP

Post Office Protocol (POP) is an internet standard that makes it possible to download email messages from an email server to a computer. POP has been updated twice since its origin in 1984 as POP1. Post Office Protocol Version 2 (POP2) was published in 1985. Post Office Protocol Version 3 (POP3) was published in 1988 and included new authentication mechanisms and other actions.

How POP Works

Incoming email messages are stored at a POP server until you log in (with an email client) and downloads the messages to your computer. The POP standard doesn't include the means to send messages. Simple Mail Transfer Protocol (SMTP) is used to send emails.

How POP Compares to IMAP

POP and Internet Message Access Protocol (IMAP) are similar in that both are used for email retrieval. However, POP is older and defines only simple commands for email retrieval. IMAP enables synchronization between devices and online access. With POP, messages are stored and managed locally on one computer or device. Therefore, POP is more straightforward to implement and typically more reliable and stable.

Disadvantages of POP

POP is a limited protocol that allows an email program to only download messages to a computer or device, with an option to keep a copy on the server for future download. While POP lets email programs track retrieved messages, sometimes this process fails, and messages might download again. Also, with POP, it's impossible to access the same email account from multiple computers or devices and have actions synchronize between them.