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Glossary Home

What will I learn?

  1. What is POP?
  2. How POP3 works?
  3. Comparison between POP and IMAP
  4. Pros and cons of using POP3 protocol
  5. Use cases for POP3

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Glossary Home

Post Office Protocol (POP)

What is POP?

The Post Office Protocol (POP) is an old yet simple email protocol used to fetch emails from a mail server and store them in a local device. With the POP3 version, users can download emails from a mail server and save them to their computer, laptop, or mobile device.

How POP3 works?

The POP protocol allows users to retrieve emails from the server and save them locally so that the emails can be viewed without the internet. In most scenarios, the emails are deleted from the server the moment they are downloaded to the user’s local storage. This caters to people who require offline access to emails when there is no internet connectivity. 

Ideally, there are two stages when using a POP3 protocol to fetch emails. They are:

Connection and authentication

The first stage while using a POP protocol is when an email client establishes connectivity to a mail server. With valid internet connection, the user credentials are authenticated before communicating with the mail server to access the emails.

Download and delete

The system downloads and deletes the emails upon successful connection and authentication.

Note:

By default, emails are deleted from the mail server once they are downloaded. However, certain email solutions allow you to retain copies of emails on the server for a specific duration.

Comparison between POP and IMAP

The POP protocol does a one-way sync to retrieve emails, and there is no sync between the email clients and the server. Most business email providers support configuring POP and IMAP. The table below provides an overview of the features supported by both POP and IMAP protocols and helps you make informed decisions while choosing one.

POP vs IMAP
POPIMAP

Storage in a local device

  • Emails are saved to the user's computer.
  • POP consumes local storage space as the emails are downloaded to the device.
  • Recommended for users who access their email from one device.

Stored in mail server

  • Emails are synced to one or more email clients while the original copy is retained in the mail server.
  • IMAP saves local storage space as the emails are stored on a remote server.
  • Recommended when emails are to be accessed from multiple devices.

Accessing emails

  • View your previously downloaded emails at any time, even without the Internet. 

Accessing emails

  • It is mandatory to have a valid internet connection to communicate with the mail server and access the emails.

One-way sync:

  • Emails are retrieved from the server without any further sync between the server and the client.
  • The read/ unread status of the emails is not maintained.
  • Actions performed on the emails (delete, move, etc.) are reflected only in that particular client.

Two-way sync:

  • Emails are continuously synced both ways between the server and multiple email clients.
  • The read/ unread status of the emails is maintained.
  • Actions performed on the emails (delete, move, etc.) are reflected across all devices.

Pros and cons of using POP3 protocol

POP is a simple protocol that organizations can still implement for their users based on specific requirements, such as offline usage or when they work in regions with limited network availability. Following are some of the pros and cons of POP.

Pros

  • Offline access: Once emails are downloaded, they are stored locally, allowing users to access them without an internet connection.
  • Server storage savings: Since emails are downloaded and often deleted from the server, it reduces the amount of storage space used on the server.
  • Simplicity: POP is simpler than IMAP in terms of setup and usage, making it ideal for users who want a straightforward email experience.
  • No server dependency for access: POP allows users to be independent of connectivity to the server.

Cons

  • Two-way sync: There is no two-way synchronization. Since emails are downloaded to a single device and often removed from the server, they cannot be accessed from other devices. Due to this, chances are high that users lose their emails when the device is lost or corrupted.
  • Folder structure: POP does not maintain the folder structure or the email's read/ unread status making it difficult to manage emails effectively.
  • Legal and compliance: If emails are lost, organizations can face legal and compliance issues. If the device is deemed unfit due to outdated versions, platform compatibility issues, or natural disasters such as a fire accident or flood, emails that were downloaded and deleted from the server can be lost.
  • Limited features: The unavailability of features such as filtering, flagging, or folder management can make it difficult for users to manage their emails.

Use cases for POP3

In spite of being an older protocol, POP is best suited in a few scenarios such as,

Single-device email use

POP is a good option for users who typically access their emails from one device, like a desktop computer or laptop, and don’t need to synchronize across multiple devices.

Limited internet access

Users who often work offline or have intermittent internet access can benefit from POP, as it allows them to download emails and read them without needing a constant connection.

Storage and load savings on email servers

For users with limited server storage or who prefer to manage their email locally, POP helps by removing emails from the server after they are downloaded, freeing up space.

Private local email management

Users who value privacy and wish to keep all their emails locally on their device, without storing them on the cloud or a remote server, may prefer POP.