Setting up a new email account should be simple, right? But then you’re asked to provide your “POP3” settings, and suddenly it seems that you need a degree in computer science.
Every day, thousands of people face this confusion when trying to add their email address to their favorite email app. That’s why we decided to explain what POP3 is, how it works, what it’s used for, and more using easy-to-understand terms.
What is POP3?
What you’ll learn in this guide:
First Things First:
What Is POP3 (Post Office Protocol)?
➡️ POP3 is the third version of the Post Office Protocol, and the purpose of this email protocol is to enable clients to download messages from servers.
In practice, a client is typically your email app (like Outlook or Apple Mail), and the server is where your email provider (like Gmail or Yahoo) stores your messages. Thanks to POP3, clients know exactly how to ask servers for messages, and servers know exactly what to do in response. In other words, POP3 is like a language that most email apps and servers understand.
The first version of this “email exchange language” was created in 1984, and two other versions have followed since then. Perhaps surprisingly, the third version of POP, which is commonly used today, was first released just four years after the first version, in 1988.
A successor to POP3 called POP4 was informally proposed in 2003 to add features like folder management. However, it never gained widespread adoption, and it will probably never be released because the Internet Message Access Protocol (IMAP) is now widely used, offering many advantages (more about them soon).
Good to Know:
How Does POP3 Work?
Just like a postal worker delivers letters to your physical mailbox, POP3 delivers emails from your email provider’s server to an email app on your computer or mobile device.
Here’s a simplified explanation of how the process works:
- Your email app (like Outlook or Apple Mail) connects to your email provider’s server using your account details.
- The server checks if you have permission to access the mailbox by verifying your username and password.
- Your email app asks the server, “Do you have any new messages for me?”
- The server responds with a list of new messages.
- Your email app downloads each message to your device.
- By default, the server then deletes the downloaded messages from its storage.
- Your email app disconnects from the server.
The most important thing to understand about POP3 is that it typically moves your messages from the email server to your device (step 6). This means that once you’ve downloaded your emails, they only exist on the device you used to download them and are no longer stored on the server unless you explicitly choose to leave them there (provided such an option is available to begin with).
POP3 vs IMAP:
What Are the Differences Between POP3 and IMAP?
Modern email users expect their messages to be available everywhere, just like their social media accounts, cloud storage, or any other online service. When you read an email on your phone, you expect it to show as “read” when you check it later on your computer. When you sort messages into folders on your laptop, you want to see the same organization on your tablet. Unfortunately, all this isn’t something POP3 can do.
As explained in the previous section, POP3 typically moves your messages from the server to your device so that only one copy remains. Additionally, the protocol doesn’t have any concept of folders, leaving more advanced inbox management up to individual clients.
➡️ For these reasons, POP3 is rarely the best choice for modern email users, who usually need to access their messages from multiple devices and keep their inbox organized across all of them.
💡 The fundamental difference between POP3 and IMAP:
Instead of removing downloaded messages from the server, IMAP keeps them stored there and only downloads a copy to your device for offline access. The status of these local copies is then synchronized with the originals on the server. This fundamental difference between POP3 and IMAP is why the former protocol is recommended mostly for legacy purposes – not everyday use.
Other differences between POP3 and IMAP include:
- IMAP can notify you instantly when new emails arrive, while POP3 only checks for new messages when you tell it to.
- IMAP lets you search through your emails directly on the server without downloading them first, while POP3 requires downloading all messages before you can search them.
- IMAP lets you preview message content or download attachments separately, while POP3 requires downloading the entire email with all attachments.
- Clearly, IMAP is far more capable than POP3, but the extra complexity required means that you’re more likely to encounter synchronization issues and conflicts. With POP3, errors are quite rare, and they can usually be troubleshot with relative ease.
Easy Trouble Shooting:
How to Fix Common POP3 Connection Issues?
When setting up and using your email using POP3, you might encounter various connection errors. These are the three most frequent errors:
Wrong Port Number
One of the most frequent causes of POP3 connection errors is using incorrect port numbers. POP3 typically uses these standard ports:
- Port 110: Standard, unencrypted POP3 connection
- Port 995: Secure POP3 connection (POP3S) using SSL/TLS encryption
If you’re getting connection errors, such as “Cannot connect to server” or “Connection timed out”, then first check if you’re using the correct port.
Incorrect Login Details
Another common issue occurs when your username or password isn’t recognized. This usually results in an “Authentication failed” or “Login incorrect” error. To resolve this:
- Double-check your email address (username) for typos.
- Verify your password is correct.
- Try resetting your password if you’re unsure.
To avoid login issues in the future, consider saving your credentials using a reliable password manager like Bitwarden, which is free and open source.
Inbox Size Limits
Most email servers limit how large your inbox can be. When it becomes full, you might start receiving error messages. The solution is obvious: delete unnecessary emails, especially those with large attachments. If you have the “leave messages on server” option turned on, then this is a good time to consider whether it wouldn’t be better to disable it.
Depending on how large the maximum size of your inbox is, you might want to consider switching to an email provider that offers more storage space. While migrating to a new email service might seem daunting, modern email migration tools like MailJerry can help you transfer all your messages and folders in just a few steps.
What is POP3?
Our Conclusion
POP3 has been serving email users reliably for decades, its simplicity both a strength and a limitation. Hopefully, you now better understand what POP3 is, how it works, and how it differs from its more capable sibling, IMAP.
➡️ Though there are good reasons to rely on POP3 (such as mailserver limitations), IMAP is generally the better choice for everyday email use.
