Knowledge base

Sending domains

At MailerSend, you can send transactional emails using your own domain name. A sending domain is your unique identifier in the MailerSend application.

Before you can start sending emails from your domain, you need to add and verify it. Read our help article on How to add and verify your sending domain for instructions.

Once your domain is verified, it’s time to let the good times roll! 

Your domain name is unique for your account, and there can only exist one of the same domain among all accounts using MailerSend.

You can have more than one domain under your personal account, and each domain can have different settings (they are not related to each other). For example, if you set to track opens or unsubscribes for one domain, another domain that belongs to your account can use different settings.

How to manage domains

All domains that belong to your account are listed under the Domains page. You can access this page from the left-hand navigation menu. Once you’re there, select the domain you want to see or change settings for by clicking Manage.


View of the domain's statistics.

When you select a domain, the first section you see is the basic statistics. Here you can check how many emails have been processed, how many were successfully delivered, how many were rejected and how many have been received.

  • Processed defines the number of emails that you tried to send through the MailerSend email API endpoint.

  • Delivered defines the number of emails that went through the MailerSend email API endpoint and have been successfully delivered to the provided recipients. 

  • Rejected defines the number of emails that didn’t go through. Usually, these are bounces or suppressed email addresses. Please read more about suppressed email addresses in this article.

  • Received defines the number of emails received if an inbound route has been added.

API tokens

API tokens are used for authentication when sending emails or accessing server-specific endpoints. They’re the preferred alternative to using a username and password, as you can revoke an API token at any time and use different permissions.

Tokens are generated under your domains, but you can access other domains using the same token belonging to your account too.

Read more about API tokens in this article.

Tracking details

When sending emails with MailerSend, you can enable tracking for a specific domain. This feature is helpful when you want to know how your recipients interact with your emails. 

You can choose between open, click, unsubscribe and content tracking.

Read more about domain tracking options in this article.

Sending instructions

On this page you can find details on how to start sending emails from your domain. We’ve included the most important examples to give you an idea.

If you want to know more about how to start sending emails through MailerSend, please read this article.

Sending emails from a subdomain

You can send emails from any subdomain associated with a verified domain, without having to verify the subdomain. To do this, simply enter the email address belonging to the subdomain in the From field of the email. 

Emails sent from a subdomain will be signed with the associated top-level domain (TLD), meaning that all analytics will fall under that TLD. If you would like dedicated statistics for a specific subdomain, you will need to add the subdomain and verify it.

Advanced settings

Under the advanced settings you can see all additional things that you can do with your domain, such as manage the unsubscribe page and suppressions.

Unsubscribe page

When using MailerSend, you can enable unsubscribe tracking for your domain. Please refer to this article to read more about tracking details (including unsubscribe tracking).

When unsubscribe tracking is enabled, you might want to control how the unsubscribe page looks and works. In this section, you can edit the design of your unsubscribe page.


Suppressions is the list of email addresses that will be rejected during the sending process. In this section, you can see how many emails have been rejected during your sendings.

Read more about suppressions here.

Precedence header

Premium users can enable the “Precedence: Bulk” header for any of their domains. Doing so will insert a header into all emails sent via the API and the SMTP relay to inform Gmail that you intended to send a bulk email. This ensures that your email avoids the spam folder, and Gmail doesn’t return any auto-responder messages to your inbox. 

To enable the “Precedence: Bulk” header via the UI:

1. Go to Domains and click Manage next to the domain you want to enable the header for. 

2. In Advanced settings, click More settings and then toggle Add precedence bulk header on.

Screenshot showing the precedence header option enabled in MailerSend.

You can also enable the header via the “Update domain settings” endpoint.

To do so, use the following PUT request:


And use the “precedence_bulk” parameter to enable the header.

Read more about the domain settings endpoint.

Danger zone

Screenshot showing the domains danger zone in MailerSend.

We call this section a danger zone for a reason, so be careful. In this section, you can stop sendings and delete domains. These actions can directly affect your sendings.

How to stop sendings

You can pause sendings at any time. In order to do that, you need to click on the Stop sending button. Once stopped, our servers will accept your API requests but none of the emails will be delivered.

Once sendings are stopped, MailerSend accepts all API requests and stores them into the queue. While requests are stored, two buttons are available: Resume sending and Clear queue.

If you choose to Resume sending, all API requests that are stored will be processed. This means that MailerSend will send all the emails that didn’t go out while sendings were stopped. 

If there is a need to not send emails that have been stored in the queue, you need to click on the Clear queue button and then click on the Resume sending button. This will clear all emails that were collected while sendings were stopped.

How to delete a domain

If you decide to delete a domain, you can do this here. After selecting the domain to delete,  a confirmation message will appear where you need to agree to the deletion. This action cannot be undone!

Screenshot showing the domains danger zone in MailerSend.

All emails that are sent through the domain will be rejected immediately and all information will be deleted, including activity and analytics.

Need more info?

Please feel free to contact us at and a member of our support team will gladly assist you.

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