Email Essentials: What is the Outbox in Email?

What is Outbox in Email

Many people assume emails work like chat messages — once you hit the Send button, your email magically appears in the recipient’s inbox. But it’s a bit more complicated, as there is a technical process that starts once you hit Send. 

Think of the outbox as a waiting room for your emails before they catch a flight. Your email client has to communicate with mail servers before it can send your message out into the internet.

But what is the need for it, and what can you do if your email gets stuck in the outbox? This in-depth guide breaks down the email outbox and its mysteries.

Table of Contents

What is the Outbox in Email?

The “outbox” is a folder or queue within your email client or service interface where outgoing messages are temporarily stored before they are actually sent to the recipients. When you compose an email and click the “send” button, the email is not immediately transmitted to your recipient’s inbox — instead, it is first placed in the outbox.

Emails in the outbox stay in this waiting phase until the email client initiates the sending process. Think of a boarding gate at the airport, where you would wait for a final check before you board a plane and fly off.
After attempting to send the emails, the email client receives confirmation or error messages from the email server. If the sending is successful, the email moves to the “Sent mails” folder. If there are issues (if the recipient’s address is invalid or the server is down), the email client may keep the email in the outbox and try to send it again later.

The outbox is particularly useful when you are offline or not connected to the internet. In such cases, the emails are stored in the outbox until a connection is reestablished, and the email client can proceed with sending them.

Outbox vs. Sent Mail

People wrongly assume that the sent emails folder is the same as the outbox. As the outbox isn’t prominently visible in the navigation pane on the left side of the mailbox, not many users are familiar with its role. Here is a table explaining the biggest differences between these two features. 

FeatureOutboxSent Folder
FunctionTemporarily stores outgoing emails before sending.Stores copies of successfully sent outgoing emails.
Status of emailsEmails in the outbox are pending and have not been sent yet.Emails in the sent folder have been successfully sent.
User interactionUsers can review, edit, or cancel emails in the outbox before sending.Users typically cannot edit emails in the sent folder. They are read-only.
Temporary storageServes as a temporary holding area for outgoing emails.Serves as an archive of sent emails for reference.
Error handlingIf there are issues with sending, emails may stay in the outbox for troubleshooting.Emails only make it to the sent folder once they are successfully sent; in case of any errors, they will either be in the drafts folder or the outbox.
User controlProvides users control over when to send emails and the ability to make last-minute changes.Serves as a record; users can review past sent emails but cannot control their delivery.
Outbox vs Sent Folder: Differences

In short, you still have control over the emails in your outbox; the sent folder is for emails that have already been sent, and there’s nothing you can do to undo the action.

Outbox and Drafts: Is it the Same Thing?

If emails are unsent messages, it’s the same as email drafts! You’d think so, but no. Below, we explain the characteristics that differentiate these two email functionalities. 


  • The outbox is a temporary holding area for emails that have been composed and are ready to be sent. 
  • When you click the send button, the client moves the email to the outbox before transmitting it to the recipients. Emails in the outbox are in a pending state, waiting for the email client to initiate the sending process.
  • It is used for emails that are actively in the process of being sent, and it lets users review, edit, or cancel the email. It is advantageous when you are offline or experiencing connection issues.


  • The drafts folder is a place where you can save incomplete or unfinished emails that you are still working on. Drafts are not actively in the process of being sent. 
  • They are essentially placeholders for emails that you might want to revisit and complete later.
  • Drafts can be useful for situations where you need to step away from composing an email and come back to it at a later time. It’s a way to save your progress without actually sending the email.

Where is My Outbox?

The location of the “Outbox” in your email client can vary depending on the email service or program you are using, but it’s typically easy to find.

Here are general instructions for finding the outbox in common email clients:

Outlook (App)

To see the outbox on Outlook, follow these steps:

  1. Open the Outlook app.
  2. In the navigation pane, under items like Inbox and Drafts, you should see the “Outbox” folder. Click on it to see unsent emails.
Outlook App Outbox Location
Outlook App Outbox Location

Note that the outbox function won’t be visible to you unless you are offline or something else is stopping the email’s sending process. If everything is functioning normally, Outlook hides the outbox. That’s why the web version never shows you an outbox — you need internet connectivity to access Outlook on the internet.


The outbox folder is no longer visible on the Web version of Gmail or on the official iPhone app for Gmail.

To view the Outbox on your Android phone:

  1. Open the Gmail app.
  2. At the top, click on the three-line menu on the left side of the search bar.
  3. In the pane that opens up, you should see the Outbox folder under the Scheduled folder.
Gmail on Android Outbox Location
Gmail on Android Outbox Location

Apple Mail

As in the case of the Outlook app, the outbox folder only appears when you’re offline or you’ve made an error typing the email address. 

Here are the steps to find the Outbox on Apple Mail:

  1. Open the Apple Mail app.
  2. Right at the top, under Mailboxes, you should be able to see an Outbox.
  3. Clicking on it will display all unsent emails.
Apple Mail Outbox Location
Apple Mail Outbox Location

Mozilla Thunderbird

Finding the Outbox in Thunderbird goes like this:

  1. Open Thunderbird.
  2. In the left sidebar, right at the bottom, you can see the Outbox folder.
  3. Click on it to view the emails waiting to be sent.
Thunderbird Outbox Location
Thunderbird Outbox Location

Remember that these instructions are general and might vary slightly depending on the specific version of the email client you are using. If you’re having trouble finding the outbox, you can refer to the help documentation or support resources for your specific email client.

The Role of the Outbox in Email Marketing

In the context of email marketing, the outbox refers to a feature within an Email Service Provider (ESP) or marketing automation platform UI. This outbox holds your scheduled or drafted email campaigns before they are sent to the intended recipients. 

Here are the steps that involve the usage of the outbox folder:

  • You may choose to schedule your email campaigns for a specific date and time. This is where the outbox comes into play — the scheduled emails sit in the outbox until the designated time arrives.
  • Before emails go out to your entire subscriber list, ESPs often perform various checks. This can include spam checks, testing different email clients, and ensuring that your content meets industry standards. The outbox provides a final checkpoint before emails are dispatched.
  • Some ESPs use the outbox to control the rate at which it sends emails. This is called throttling. By gradually releasing emails from the outbox, ESPs aim to maintain good deliverability rates and avoid being flagged as spam.
  • In case of any issues during the sending process, such as network problems or server issues, the outbox can act as a safeguard. Emails remain in the outbox until the issues are resolved, preventing incomplete or failed email deliveries.
  • Select ESPs allow you to cancel or edit scheduled emails that are still in the outbox. This flexibility is useful in case you want to make last-minute changes or if there’s a need to halt the campaign.

Note that the specific terminology and features can vary among different ESPs. Marketers should familiarize themselves with the tools and features provided by their chosen email platform.

Email Stuck in the Outbox?

An email might get stuck in the outbox for various reasons, and troubleshooting the issue can depend on factors like your email client, network conditions, and server configurations. 

If your email is stuck in the outbox, check if any of the following reasons could be behind it:

  1. Poor internet connectivity,
  2. Emails with large attachments,
  3. Problems with the outgoing mail server,
  4. Email size limits,
  5. Incorrect or incomplete email addresses,
  6. Complications with the firewall or antivirus software,
  7. Bug in your email app,
  8. Email client configuration issues,
  9. Your server is blacklisted.

When troubleshooting, it’s essential to check your email client’s error messages, review your email settings, and consider the specific circumstances surrounding the issue to identify the most appropriate solution. 

How to Send Emails Stuck in Outbox

Here are the best troubleshooting steps to try if your emails refuse to leave the outbox.

  1. Close and reopen your email client to refresh its connection.
  2. Test to see if your internet connection is stable and working.
  3. Double-check the recipient’s email address.
  4. Reduce the size of the attachments or use file-sharing services.
  5. Confirm that your email client has the correct SMTP server settings.
  6. Temporarily disable your firewall or antivirus.
  7. Try resending the email. 
  8. Verify if your email provider is experiencing any server issues.
  9. Look for error messages or notifications in your email client.

Wait for some time and then attempt to send the email again. If you’re unsure about any settings or need more specific assistance, don’t hesitate to reach out to your email provider’s support team for guidance.

Campaign Refinery: Flawless Email Sending

There are various reasons why you may frantically rush to your outbox to stop your campaign emails from going out — perhaps you saw a design error, or you realized your email list has a bunch of invalid emails, maybe you want to add content, or maybe the formatting is completely off, or possibly the personalization settings went haywire.

We can’t speak for human error, but the chances of running into technical errors at Campaign Refinery are really small, thanks to our brilliant development and testing teams.

We built our email platform to be exceptionally simple yet powerful. If there are errors, you will see them in advance. 

For example, your email lists will always be problem-free, thanks to our automated cleaning feature. Our email testing tools will catch any design flaws, as well as formatting issues. As for our automation tools, they’re extremely intuitive and will do exactly what you want them to do. And if you create a schedule for your emails, they will go out with precision.

In return, ESPs will reward you with excellent deliverability — that’s why ours is the best in the industry. Our commitment to being a top-tier email platform has brought us rich rewards!

And if you’d like to know how the top 1% of email senders operate, apply to join Campaign Refinery today!

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