POP3 vs. IMAP: Breaking Down the Basics 

pop3 vs imap cover image with a plane carrying a space shuttle

POP3 and IMAP are both technologies that pull your messages from the email server to your device, but they work differently. POP3 limits you to checking your emails on just one device. In contrast, IMAP syncs your emails across multiple devices, letting you view them anywhere without removing them from the server.

When setting up your email on clients like Outlook or Thunderbird, you’ll encounter a choice between two key protocols: POP3 vs. IMAP. While both serve the same basic purpose, they come with distinct differences. 

Let’s cover how POP3 and IMAP work, their advantages, and discover which might be the best fit for your emailing needs.

What Is POP3?

The Post Office Protocol Version 3 (POP3) is a way to get your emails from the server to your local devices. Created by Joyce K. Reynolds in 1984, POP3 downloads your messages and then removes them from the server. 

The biggest benefit of POP3 is that you can access your email messages even when you’re offline. The messages are already downloaded to your device, so you don’t need an internet connection. 

POP3 uses two ports to connect to your email server: 110 and 995. Port 110 is for standard, non-encrypted email, so it’s less secure. For a secure connection that encrypts your emails, it switches to port 995, which uses Transport Layer Security (TLS) and Secure Sockets Layer (SSL). This ensures your email communications are safe and private.

How Does POP3 Work?

Let’s break down how POP3 works: 

  1. Your email client securely logs in to the server with your username and password.
  2. It requests a list of your messages from the server, showing their sizes and numbers.
  3. You select which emails you want to download.
  4. Your email client asks the server to send those specific messages.
  5. The server sends the selected messages, and your device downloads them.
  6. The downloaded messages are removed from the server.
  7. Your email client confirms the messages have been received.
  8. The communication line between your email client and the server is closed.

Think of POP3 as a trip to the post office: you unlock your mailbox with a key (log in), pick up letters, and take them home (download to your device). With a nod to the post office worker (confirmation of receipt), you head home to read your mail whenever you want, similar to accessing your emails offline after the session ends.

POP3 Pros and Cons 

The highlight of POP3’s advantages is its simplicity and flexibility. 


  • Offline access: Once you’ve downloaded your emails, they’re on your device. So, you can view them without an internet connection.
  • Works fast. Accessing messages stored directly on your device is quick and efficient. 
  • Saves server space: Since emails aren’t on the server, you won’t need to worry about buying more server storage space.
  • Simple to set up and use. POP3 is straightforward to configure because it doesn’t involve syncing messages across devices. 


  • Security risks: Downloading files to a physical device makes them susceptible to any security threats that the device faces. If your device gets a virus, your emails could be compromised.
  • Risk of loss: You might accidentally delete the emails on your device, or they could get damaged. Without a server backup, you might lose them forever.
  • Storage demands: Keeping all your emails and attachments on your device can require a lot of storage space, which might be a challenge for devices with limited capacity.

What Is IMAP?

The Internet Message Access Protocol (IMAP), created by Mark Crispin in 1986, is a solution to one of POP3’s major limitations: the ability to access emails only on a single device. 

Instead of downloading emails to a device, IMAP lets you view them directly from the server. This way, you won’t need to download your messages from the server, which saves both time and storage space.

What’s more, it synchronizes across all your devices. If you open an email on your phone and mark it as read, that change reflects on your laptop or tablet, too. This seamless sync ensures that your inbox looks the same, no matter where you access it from. 

IMAP operates securely using TLS and SSL encryption — over ports 143 and 993.

How Does IMAP Work?

Let’s break down how IMAP simplifies managing your emails:

  1. Once you’ve entered your username and password, the server gives you access to your emails.
  2. Initially, you’ll only see a snapshot of your messages, including the subject line and the senders. This information gets stored temporarily on your device.
  3. If you decide to open a message, your email client will retrieve the entire message from the server. 

Think of IMAP as a library for your emails. You walk in and see titles and authors (subject lines and senders) without taking any books off the shelf. If you want to read a book (open an email), you pick it up, read, and then put it back. You can come back and read the book again, without ever needing to take the book home with you.

IMAP Pros and Cons 


  • Multi-device access: IMAP lets you access and manage your emails from any device. Since messages are on the server, they’re tied to a single device.
  • Resilience to device failure: Your emails are always accessible on other devices even if one fails. So, there’s a much lower risk of data loss.
  • Minimal storage requirement: Your emails get cached, not stored, on your device, which means you’ll need less storage space. Plus, attachments need space only when you download them.
  • Easier email management: IMAP lets you easily organize emails with options to create, delete, or archive messages and folders.


  • Constant internet need: You always need internet access to check your emails. Without a connection or if the servers go down, you can only see the messages that were cached on your device. 
  • Security concerns: Keeping emails on IMAP servers means potential email security vulnerabilities. Despite using encryption, the risk of cyber threats exists, especially if the server doesn’t implement email security best practices, such as encrypting and hashing your passwords. 
  • Slower speed: Fetching emails from the server can be slow, especially on poor internet connections.
  • Server space limitations: While the default server space may be enough for many people, users with large email volumes might need to buy additional storage.

Let’s recap POP3 vs. IMAP advantages and disadvantages. 

*Advantages Disadvantages 
IMAP‣ Synchronization across devices
‣ Low storage requirements
‣ Not affected by device limitations
‣ More control over messages
‣ Doesn’t work without an internet connection
‣ Security issues
‣ Lower access and retrieval speed
POP3‣ No internet connection
‣ Fast access
‣ Low storage space on the server
‣ High storage space on the device 
‣ Vulnerable to device security issues
‣ Prone to damage and corruption
IMAP vs. POP3 pros and cons

IMAP vs. POP3: How Are They Different? 

IMAP and POP3 both act as intermediaries between your local devices and email servers to fetch your emails. 

Still, they’re different. Let’s explore the differences between IMAP and POP3. 

Download locationOn serverOn the device
Deletes files NoYes (although settings can be adjusted to keep files)
Access Multiple devicesSingle device 
Email adjustment and organizationAllowed Not allowed
Encryption Yes (Ports 143, 993)Yes (Ports 110, 995)
Constant internet accessYesNo
Device storage consumption LowHigh
Message loading speedLowHigh
Control over downloading Only the email header is downloaded All parts are downloaded automatically 
IMAP vs. POP3 differences

POP3 vs. IMAP: Which One Should I Choose?

When POP3 was introduced, most people didn’t have fast or reliable internet connections. So, a reliable way to download all emails in one go was a lifesaver. But now we have speedy internet access almost everywhere, making it easy to check emails whenever we want. Plus, accessing email messages on multiple devices is the norm these days. 

Both protocols can work with all email servers today. So, the choice between POP3 vs. IMAP email protocols depends on your needs and preferences. 

So, choose POP3 if you:

  • Have a slow internet connection and prefer downloading all your emails at once.
  • Don’t want to purchase cloud storage from email service providers. 
  • Like to keep your emails on a physical device rather than in the cloud.
  • Only use one device to access your emails. 

However, IMAP is often the better choice for many because it’s more modern, versatile, and user-friendly.

So, pick IMAP if you:

  • Want to check your emails on various devices.
  • Don’t want to immediately download all your attachments. 
  • Have reliable internet access and prefer seeing your emails immediately.
  • Like the idea of storing emails in the cloud instead of on a single device.
  • Need to manage, change, and synchronize your emails across devices.
  • Share your email account with others.

As an email sender, you can be almost sure that your recipients are using IMAP. But in the odd scenario that someone uses POP3, it’s a good idea to allow access to your email content through other means, such as a website, especially if the email contains important information. You never know if the email that POP3 deletes might come in handy. 

IMAP vs. POP3 vs. SMTP

When you look into email protocols, you’re bound to come across SMTP. Simple Mail Transfer Protocol is the workhorse of email. It moves messages from one email server to another and from your device to the email server. It runs on the TCP/IP protocols and listens to port 25. 

So, how does SMTP compare to POP3 and IMAP? 

The key difference lies in their functions: SMTP is designed for sending emails, while POP3 and IMAP are focused on retrieving emails. 

In other words, IMAP and POP3 manage incoming messages, while SMTP manages outgoing messages for an email account. 

Unlike POP3 and IMAP, where you have the freedom to choose based on your needs, SMTP is a universal standard for sending messages. It’s part of how email works across the internet.

Email POP3 vs. IMAP vs. Exchange

Exchange is another term thrown around when it comes to email-receiving protocols. 

The main difference between POP3 vs. IMAP vs. Exchange is that POP3 and IMAP are protocols, while Exchange is a server solution. This means it can use protocols to send and receive emails. 

Microsoft Exchange uses a proprietary protocol known as Messaging Application Programming Interface (MAPI). You can use Microsoft Exchange both as a cloud solution or on premise. It provides a robust set of features designed to ensure a smooth, integrated experience across multiple devices. 

Exchange is different from IMAP and POP3 in three areas: 

  1. Storage management. 
  2. Synchronization. 
  3. Email client compatibility. 

Let’s unpack these differences. 

Firstly, while IMAP typically stores inbox messages on the server and outbox messages on your device, Exchange can keep both inbox and outbox messages on the server. This comprehensive storage solution facilitates better email synchronization and management. 

Secondly, Exchange can synchronize contacts and calendars, not just emails. This is something you don’t get with POP3 and IMAP.

Finally, IMAP and POP3 are compatible with any email client, but Exchange is particularly optimized for Outlook.

How to Set up Your Email Account with POP3/IMAP

Setting up your email to send messages with different email clients is pretty simple. Just go into the settings of your email client and look for the right options to adjust. Let’s cover how you do it with Gmail and Outlook. 

Setting Up POP3/IMAP for Gmail

To access POP3 vs IMAP settings for Gmail, follow these instructions: 

  1. Open your Gmail account on a browser. 
  2. Click the gear icon in the top-right corner. 
  3. Click “All Settings.”
  4. Find “Forwarding and POP/IMAP in the top panel and click it. 
  5. Once inside the menu, you can see the settings and the enabled protocol. You can select your desired protocol by clicking the circle next to each option. 

This is how your settings should look: 

gmail server settings
Gmail POP3/IMAP settings

Setting Up POP3/IMAP for Outlook 

The default protocol for Outlook is IMAP — unless you have an Exchange server in your organization. So, if you don’t want to use POP3, keep the settings unchanged. 

However, to enable POP3, go through the following steps: 

  1. Open your Outlook account and go to Settings by clicking the gear icon.
  2. Click Mail > Sync Mail. 
  3. Go to POP and IMAP > Let devices and apps use POP.
  4. Select Yes.
  5. Save changes. 

Check out this screenshot: 

POP3 settings in Outlook
POP3 settings in Outlook

How Do I Know if My Email Is POP3, IMAP, or Exchange?

Figuring out whether your email uses POP3, IMAP, or Exchange is pretty straightforward. 

Here’s how you can check:

  • Your email settings: Most email clients let you see your account settings, where you can find the type of email protocol you’re using. 
  • How your email behaves across devices: If your emails stay in sync across multiple devices (when you delete or read an email on one device, it updates on all others), you’re likely using IMAP or Exchange.
  • Features you use: If you’re using features like shared calendars, contacts, and tasks, and everything is seamlessly integrated, there’s a good chance you’re using Exchange, especially if you’re in a workplace environment.
  • Your server settings: In your email settings, there should be a section for server settings that includes incoming and outgoing server details. This will mention which protocol you’re using. 

Should I use POP3 or IMAP on My Phone?

If you check your email on your phone and also use other devices, IMAP is the way to go. It lets you keep all your emails in sync across every device. Nowadays, it’s the default choice in almost all scenarios. 

Even if you’re just using one email account on your phone, we still recommend IMAP. The main reason is the limited storage on mobile devices. Using POP3 means all your emails are stored on your phone, which can quickly fill up its storage.

Does Gmail Use POP3 or IMAP? 

Gmail gives you the choice to use either POP3 or IMAP for your email, so it’s up to you. 

When you access your Gmail through a web browser (webmail), it doesn’t really matter what protocol is used because the technical stuff happens behind the scenes. You’re just using the internet to check your mail. 

However, when you’re setting up Gmail on an email client (like Outlook or the Mail app on your phone), you can choose between POP3 vs. IMAP.

Boosting Deliverability, Connecting on Every Device

At Campaign Refinery, we’re passionate about sending your marketing messages on a journey straight to your audience’s inboxes, no matter the device. 

Why does this matter? Because in the bustling digital bazaar, your emails need to be more than just received — they need to be experienced. 

Whether your audience is scrolling through their phone in a coffee shop or clicking through their desktop at work, we make sure your campaigns are ready to make a splash. 

Here’s what you get when you join us: 

  • Automatic list cleaning: Keep your email list pristine and performance-driven by automatically removing inactive subscribers and harmful addresses. 
  • Engagement gamification: Increase interaction and loyalty among your subscribers with our point-based system. 
  • Evergreen flash sales: Drive sales and urgency with campaigns that feel fresh and timely, and keep subscribers coming back for more.
  • Campaign library: Access a treasure trove of proven email campaign templates designed to achieve your marketing goals.
  • Exclusive learning resources: Elevate your email marketing skills with our exclusive guides and tutorials tailored to help you succeed.

Let’s make your email marketing impossible to ignore. Apply to join today

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