Creating custom domains

How to use custom domains with MailSlurp. Create email addresses with your own domain and send and receive email from tests, apps, or the web app.

  • Table of contents

MailSlurp supports unlimited custom domains. Buy your domain then add it to the MailSlurp dashboard. DNS records will be generated and assigned to your account. Add these to your domain provider DNS settings to verify and enable custom email addresses.

custom domain email address

MailSlurp supports sending and receiving emails from custom domains.

We recommend following the more detailed step by step domain creation guide for more information.

Custom domains allow you to use any email address you wish under that domain. In order to use custom domains you need to verify the domain in the MailSlurp dashboard.

Registering a domain name

To use custom domains with MailSlurp you must own or have access to a domain name and DNS server settings. You can use any Domain Name Provider to purchase a domain name.

See the extended domain guide for examples.

MailSlurp domain settings

Once you own a domain you can configure MailSlurp to use it. Go to the domains page to see a list of your current domains. Click the + button to create a new domain.

domain page

Domains can be either HTTP or SMTP type domains. This determines the type of inbox you can create with the domain. HTTP inboxes are processed by AWS SES while SMTP inboxes use a custom mail server running HTTP inboxes are best for most cases. SMTP inboxes are more suited for public facing email addresses that support older email clients but are receive-only and cannot send. HTTP domains use MX records that reference AWS servers. SMTP domains use an MX record of 10

Adding a domain to MailSlurp

On the create domain page you can enter a domain name.

This should be a top level domain with no @ symbols. For instance can be used with MailSlurp to create inboxes with addresses such as

You can send from any subdomain of that domain without specifically verifying the subdomain. For example, if you verify, you do not need to verify or

create a domain

Verifying domain names

Note: All domains must be verified by adding TXT and MX records to your domain's DNS configuration.

pending domain

You can view your domain records in the dashboard domain view page. An email containing the records with also be sent to your account.

You need to add these DNS records (MX, C, TXT)to your domain's DNS setup to verify the domain and to enable MailSlurp to send and receive emails on the domain's behalf.

warning domain

DNS record entry:

dns records

Record Types

Note each account is given unique records. Login into your account to view domain records. Create a domain to view the records.

Verification record

A TXT record is generated for your domain and must be added to your domain DNS settings to allow verification.

It takes the format:

recordType = TXT,
name = "_amazonses.${domain.domain}",
recordEntries = listOf(domain.verificationToken),
ttl = 600

Example verification

  • Name: _amazonses.<your-domain>
  • Type: TXT
  • Records: <your-verification-token>
  • TTL: 600

MX Record

You must add a single MX to your domain provider to allow MailSlurp to receive emails on behalf of your domain. There are two possible MX records depending on the type of domain you create. SMTP domains can be used with SMTP inboxes. SMTP inboxes are processed by a mail server running at while HTTP inboxes are handled by AWS SES. Use SMTP for public facing inboxes and SMTP for internal or test email accounts. For more information see the SMTP vs HTTP inbox guide.

HTTP inbox

An HTTP domain has a static MX record pointing to AWS SES servers.

  • Name: <your-domain>
  • Type: MX
  • Records: 10
  • TTL: 600

SMTP inbox

An SMTP domain has an MX record that points to the MailSlurp mail server.

  • Name: <your-domain>
  • Type: MX
  • Records: 10
  • TTL: 600

Prior versions of MailSlurp included additional MX records. Do not include the following bad records as they may result in 530 errors:

  • 10
  • 10

Note on priority

MX priority is indicated by the 10 in the record value. In some hosting settings the priority should be entered into a separate field. In most providers it is included in the field directly as shown above.

SPF record

The SPF value is a way to increase the sender reputation of your domain, mail delivery, and prevent spoofing. It has a static value of v=spf1 -all

  • Name: <your-domain>
  • Type: TXT
  • Records: v=spf1 -all
  • TTL: 600

DKIM records

DKIM tokens allow you to verify a domain and prevent spam ratings. The DKIM token for you domain is displayed in the dashboard. DKIM records take the following format:

  • Name: <dkimToken>._domainkey.<your-domain>
  • Type: C
  • Records: <dkimToken>
  • TTL: 600

Test DNS Records

It is useful to test the DNS records you have added to your domain. Use the Domain Tester widget to fetch the DNS records for your domain. Make sure your records include those required by MailSlurp.


Check inside the app dashboard to view the status of your domain. If your domain is not verified after 24 hours double check your DNS records using the Domain Tester or by checking your DNS settings in your domain provider. If 72 hours passes we recommend deleting the domain and restarting the process.

Debugging common errors

See the following related articles

Creating email addresses

Once you have created and registered a domain you can create any email address you like using the Dashboard's create inbox page or via the API's createInbox(emailAddress) endpoints. See the developer's page for documentation.

Send and receive emails from custom domains

In code or the dashboard create inboxes using your custom domain.

Receiving emails with custom domains

There are many ways to receive emails with a custom domain using MailSlurp. You can view emails in the dashboard or by using the API

REST API clients

You can access inboxes you create with custom domains by using the Client Libraries or thje REST API.


Webhooks allow HTTP push of emails to your server when received by a custom domain inbox. Create an inbox webhook using the API or dashboard. See the email webhook guides for more information.