POP vs IMAP email protocols: What's the difference?
IMAP and POP are just two methods to access email. In this article, we’ll focus on demystifying POP vs IMAP. Then, we’ll look at some of the pros and cons and shed light on which of these protocols may be best for you.
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We’ve talked about how email works and how email protocols facilitate the transfer of your emails along the way, from when you hit send to when your subscriber reads your email message. But before we dive into the differences between IMAP vs. POP email, we’ll do a quick refresher on email protocols.
Table of contents
04What are the main differences between IMAP vs. POP?
What are email protocols?
There are three types of email protocols:
Simple Mail Transfer Protocol (SMTP)
Internet Message Access Protocol (IMAP)
Post Office Protocol (POP)
SMTP handles the delivery of messages. In other words, after you hit “send” in your email account the SMTP protocol transfers your message from your email client to your email service provider’s (ESP’s) sending mail server, like Mailgun’s SMTP server. The SMTP protocol continues to carry your message to your subscriber’s inbox service provider’s (ISP’s) receiving mail server and waits there until your subscriber reads your email.
If SMTP handles the delivery, POP and IMAP handle the retrieval of your email message from your subscriber’s mail server to their email client. When your subscriber fires up their email account, their email client, like Gmail, Yahoo, Microsoft Outlook, or AOL, will use POP or IMAP to download messages from the receiving mail server to their email client. The email client can be web-based, like Gmail.com, or app-based, like Microsoft Outlook.
What is POP?
POP is an email protocol that email clients use to retrieve emails from a mail server. It uses an Internet Protocol (IP) to provide an email client access to a mailbox on a mail server. Then, POP downloads messages from the server to a single computer. POP3 is the version most commonly used.
In a nutshell, POP3:
Connects an email client to an email server
Retrieves all messages from the email server
Stores the messages on the client’s local device or email client
Deletes the original message from the mail server
This is the default behavior. Sometimes, POP setups allow you to configure the protocol to leave a copy of the original message on the mail server.
What is IMAP?
IMAP is a much more sophisticated protocol designed to address the shortcomings of POP. It supports many essential features for modern email usage, such as leaving messages on the server and accessing messages from multiple devices.
In a nutshell, IMAP:
Connects an email client to an email server
Retrieves all messages from the email server
Stores the messages on the client’s local device or email client
Keeps the original message on the mail server
What are the main differences between IMAP vs. POP?
Both POP and IMAP protocols retrieve messages from your recipient’s ISP’s mail server.
Both POP and IMAP protocols retrieve emails from a mail server, but they do this differently. IMAP synchronizes emails across multiple devices, allowing users to access their messages from anywhere, while POP downloads emails to a single device and deletes them from the server by default. This makes IMAP more suitable for users who need flexibility and accessibility, whereas POP is a simpler, more lightweight option for users who prefer to store their emails locally.
What are the pros and cons of POP?
Some advantages of POP are that it:
Backward compatible with servers that don’t support IMAP
Easy to implement across most major email clients
Lightweight and straightforward to use
Saves server space since old messages are deleted by default
Some disadvantages of POP are that it:
Doesn’t support encryption. This makes POP3 less secure than IMAP
Can only be used to download messages from a server. This makes POP3 less flexible than IMAP
Can be slow since it downloads all messages from the server each time
Can take up a lot of local storage space since POP3 stores all messages locally
What are the pros and cons of IMAP?
Some advantages of IMAP are that it:
Allows you to keep your emails on the server so that you can access them from multiple devices, including your computer, mobile devices, and tablet
Allows you to access your emails offline
Facilitates searching for specific emails on your mail server
Organizes your emails into folders
Provides a secure way to access your email because your messages are stored on the mail server and not on your device
Some disadvantages of IMAP are that it:
Can be slow because it synchronizes the local mail client with the server, which can take some time depending on the size of the mailbox and the speed of the connection. IMAP generally uses more data than POP, contributing to slower speeds.
Can be unreliable because it is a complex protocol that relies on several different technologies working together. Additionally, IMAP requires more storage space on the email server than POP, leading to problems if the server needs more space.
Can use a lot of data because it constantly synchronizes the email server with the client, meaning that new emails, deleted emails, and any changes to existing emails are all downloaded to the client. This can use a significant amount of data, especially if there’s a large volume of emails.
Can be challenging to set up because it requires more complex server settings than POP.
Isn’t supported by all ESPs, which can make it difficult to use all of the features of the protocol
POP or IMAP: when to use them
IMAP supports all the essential features for modern email usage. But there are some situations where POP may be the better choice. Should you use POP vs. IMAP in Outlook? Let’s take a look at when you should use each protocol.
When should I use POP over IMAP?
When your subscriber’s receiving mail server doesn’t support IMAP
When you only access email from a single device
When your internet connection isn’t consistent
When you have limited server storage
When should I use IMAP over POP?
When you need to access your email from multiple devices
When you need to store a copy of the original email on the mail server
When your ESP supports IMAP
When your local storage is limited
When you usually have a good internet connection
If you’re wanting to connect your POP or IMAP mailbox to Mailgun, you can use Routes to send email from our platform to an IMAP/POP mailbox. We store the message body (3 days with paid accounts) and logs for those messages (30 days for paid accounts) so that our customers can pick them up through the API as the preferred method.
Final thoughts
We’d recommend IMAP over POP in most scenarios, IMAP supports remote access for multiple clients managing a single inbox. And long after its creation, this still aligns with how we need to use email.
We hope we’ve answered your questions on IMAP vs. POP but if you want to learn more about protocols, how to improve your workflow, and other niche email topics, don’t forget to subscribe to our newsletter.
