Is IMAP faster than POP3?

For a first look at a large mailbox, IMAP is usually faster because it can fetch only headers and download message bodies when you open them. POP3 must download each whole message.

Does Gmail support both?

Gmail offers both IMAP and POP access for mail apps. Google recommends IMAP for using Gmail on more than one device.

Is one more secure than the other?

Both are equally secure when used over TLS (port 993 for IMAP, 995 for POP3). The bigger risk with POP3 is losing mail if the one computer holding it fails without a backup.

Learn

IMAP vs POP3: which should you use?

Sync on every device or download to one: how the two ways of fetching mail compare.

The short answer

Use IMAP unless you have a specific reason not to. IMAP keeps your mail on the server and syncs it to every device. POP3 downloads mail to one computer and, by default, removes it from the server. If you read email on a phone and a computer, POP3 will leave each device with a different, incomplete picture.

How they differ

The two protocols were built for different worlds. POP3 (RFC 1939, 1996) assumed one computer, a dial-up connection and little server storage, so the goal was to grab the mail and hang up. IMAP assumed the server is the home of your mail and the client is a view of it.

That shows up everywhere. With IMAP, folders, read and unread status, flags and deletions all live on the server. With POP3, the server only has a single inbox. Folders, read status and your sent mail exist only in the app on that one computer.

                 IMAP                       POP3
Where mail lives  On the server              On your computer
Multiple devices  Stay in sync               Each gets its own copy
Folders           Synced                     Local only
Read/unread       Synced                     Local only
Sent mail         Saved to server folder     Local only
Offline reading   If the app caches mail     Yes, everything is local
Ports             993 (TLS), 143             995 (TLS), 110

When POP3 still makes sense

POP3 has a few real uses. If your provider gives you very little storage, downloading and deleting keeps the account under its quota. If you want a full archive on your own disk and nothing left on the provider's servers, POP3 does that by design. Some older hosting plans also offer only POP3.

Most POP3 clients have a setting to leave a copy of messages on the server, which softens the single-device problem. Even then, read status, folders and sent mail still do not sync, so your phone will show every message as new.

The risk with POP3 is that your computer becomes the only copy of your mail. If the disk fails, the laptop is stolen or you move to a new machine without migrating the mail folder, years of messages can disappear. If you rely on POP3, make regular backups (on a Mac, Time Machine covers the mail app's data).

Switching from POP3 to IMAP

If you have used POP3 for years, some old mail may exist only on your computer. Before switching, back up the local mailbox. Then add the account again as IMAP, and copy any local-only folders into the IMAP account so they upload to the server. Once that is done, every device will see the same mail.

Questions

Is IMAP faster than POP3?: For a first look at a large mailbox, IMAP is usually faster because it can fetch only headers and download message bodies when you open them. POP3 must download each whole message.
Does Gmail support both?: Gmail offers both IMAP and POP access for mail apps. Google recommends IMAP for using Gmail on more than one device.
Is one more secure than the other?: Both are equally secure when used over TLS (port 993 for IMAP, 995 for POP3). The bigger risk with POP3 is losing mail if the one computer holding it fails without a backup.