Quick answer: POP3 downloads messages from a mail server to an email application and may remove server copies depending on its settings. IMAP normally synchronises messages and folders across devices, making it more practical for many modern multi-device setups.
When configuring email, confirm your provider’s recommended incoming and outgoing settings; SMTP handles sending separately from POP3 or IMAP. See our email authentication tutorial.
Post Office Protocol version 3 or POP3 (POP), is one of the most widely used mail server protocols for retrieving email to a local device. It was designed to be simplistic and efficient, allowing users to download messages from the mails server to be stored locally whilst removing them from the server.
As a method this has been a standard for traditional email access, especially true before the widespread use of cloud-based services, multi-device syncing and more “productivity” features.
While modern alternatives like IMAP offer more flexibility, POP3 remains relevant for users with specific needs or limited server storage. For example at the moment adding custom domain email to Gmail uses POP.
How POP Works
When an email client connects to the mail server it performs the following actions:
- Authenticates the user’s credentials
- Downloads all new messages to the local device
- Deletes the messages from the server (by default, though some clients allow leaving a copy)
Because the emails are stored locally after download, users can access them offline without needing an internet connection. This makes POP3 especially useful in low-bandwidth or intermittent connectivity environments.
POP3 vs. IMAP
The key difference between POP3 and IMAP lies in how emails are managed:
- POP3 downloads and stores emails locally, often removing them from the server.
- IMAP keeps emails on the server and syncs them across multiple devices.
For users who only check email from a single device and prefer to keep control of local storage, POP3 is a practical option. However, those needing access from multiple locations or devices typically prefer IMAP.
When to Use POP3
POP3 is ideal if:
- You’re using a single desktop or laptop to access email
- You want to free up server storage space
- Offline access to your messages is a priority
However, it may not be suitable if you need device syncing or server-based folder organisation
For email choices, see business email versus free email.
POP3 or IMAP: which should you choose?
IMAP is usually better if you read the same mailbox on a phone, computer and webmail, because changes to messages and folders synchronise with the server. POP3 can suit someone who deliberately wants a local download workflow, but device-specific settings may delete messages from the server. That can cause confusion or data loss if another device also needs them.
Before switching account types, back up messages stored only on one device. Confirm the correct incoming server, secure connection, username and SMTP authentication settings with your provider. See how to create a custom domain mailbox for the starting setup.