IMAP
Internet Message Access Protocol
ELI5 — The Vibe Check
IMAP is how your email client fetches email from the server. The key thing about IMAP is that emails stay on the server, and your app just syncs a view of them. Read an email on your phone? It's marked read on your laptop too. That's IMAP magic.
Real Talk
IMAP is a protocol that allows email clients to access and manage email stored on a mail server. Unlike POP3, IMAP maintains messages on the server and syncs state (read/unread, folders) across multiple clients. Operates on port 143 (or 993 with TLS).
When You'll Hear This
"Configure the email client with IMAP to sync across all devices." / "IMAP keeps emails on the server; POP3 downloads and deletes them."
Related Terms
POP3 (Post Office Protocol version 3)
POP3 is the old-school way to receive email. It downloads all your emails to your device and (by default) deletes them from the server.
Port
A port is like an apartment number on a building. Your computer is the building (localhost), and multiple services live inside.
SMTP (Simple Mail Transfer Protocol)
SMTP is the protocol email uses to leave your device and travel to the recipient's mail server.