POP3 (Post Office Protocol version 3) is a standard email protocol used to retrieve emails from a remote server to your local device. Unlike newer protocols, POP3 typically downloads messages and removes them from the server, though you can often configure it to keep copies.

Key characteristics of POP3:

• One-way synchronization: Emails are pulled from server to device
• Local storage: Messages are stored on your computer or device
• Offline access: You can read downloaded emails without internet
• Server space conservation: Emails don't accumulate on server

Important considerations: Since POP3 usually removes emails from the server, you won't see those messages on other devices. This makes it less ideal for multi-device users who want synchronized email access across phones, tablets, and computers.

POP3 uses two common ports: port 110 (unencrypted) and port 995 (encrypted with SSL/TLS). For security, always use the encrypted port 995 when available.

While POP3 is older than protocols like IMAP, it remains useful for single-device users who want to archive emails locally and conserve server storage space. Most email clients (Outlook, Thunderbird, Apple Mail) support POP3 alongside other protocols.