Differences between IMAP and POP3 protocol
Although both protocols provide similar function – access to remote mail server in order to download email messages, IMAP is always better choice.
IMAP protocol is newer than POP3, and it offers many more functions and more optimal access to your remote mail account.
Most notable functions of IMAP protocol, that is not available in POP3, are:
- Folders. Under IMAP, you may have more folders in mail server, possibly structured in a hierarchy (like folders on computer disk). POP3 has only single INBOX folder.
Folders may be specialized, such as one for sent mail, other for trash, another for drafts, or they may be just general folders where you can sort your incoming mail.
- Selectable download of message parts. In POP3 protocol, message may be downloaded only in its entire form. In IMAP protocol, message parts may be downloaded on demand, for example only text part, or only selected attachments.
This allows faster download of what is important for user to see on a mobile device.
- Message flags stored on server. IMAP allows to store some flags besides each message on server, such as if message was already read, or it is flagged, or is a draft, etc.
- Connected mode – IMAP IDLE. In connected mode, email client may be immediately notified about changes in mailbox, such as if new mail arrived, messages were deleted, and more.
- More optimal access to data, resulting in faster responses and less network data transfer. IMAP protocol is better designed, so less data need to be transferred over network in order to access needed data.
If possible, always use IMAP protocol. Use POP3 only if your mail provider doesn’t offer IMAP access to your account. For example, some web mail services may offer only POP3 access, as POP3 is simpler and easier to implement than IMAP.