IMAP vs POP3: What's the Difference and Which Should You Use
When you set up an email account in a new app, you're sometimes asked to choose between IMAP and POP3. These are two different protocols — sets of rules — for how your mail app talks to the mail server.
IMAP: your inbox lives on the server
With IMAP, your mail app is essentially a window into your mailbox on the server. When you read, delete, or file a message, that change happens on the server itself and shows up identically on every device you check mail from.
- Read a message on your phone, and it shows as read on your laptop too.
- Folders you create sync everywhere.
- Nothing is normally deleted from the server unless you delete it yourself.
POP3: mail is downloaded and (usually) removed
POP3 was designed for an era of one computer, dial-up connections, and limited server storage. It downloads messages to a single device and, by default, removes them from the server afterward.
- Checking mail on a second device often won't show messages already downloaded elsewhere.
- Some apps let you configure POP3 to leave a copy on the server for a set number of days — but this is a workaround, not how it's designed to work.
Which should you use?
POP3 still has narrow legitimate uses — for example, archiving mail locally on a single machine with no interest in multi-device sync — but almost every provider (Gmail, Outlook, Yahoo, iCloud) defaults new accounts to IMAP for good reason.
Where to check or change this
Most modern mail apps set this up automatically and don't expose the choice at all. If you're manually configuring an account in an older app or Thunderbird, look for the option during account setup — choose IMAP unless you have a specific reason not to.