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General Guide for Custom Domain Setup

This is a general guide for the technical set up for a custom domain.
Please note this advice may not directly reflect the set up steps required by your website and/or email domain provider.

It is strongly recommended you read the following articles before proceeding:
Custom Domains and SPF, DKIM and DMARC Explained

You will need three domain records: SPF, DKIM and DMARC. If you already have an SPF or DMARC record, you can amend these to include the custom domain record values.

Domain/DNS Settings

Either your IT/Website provider or you will need access to your domain registration settings. For example, where you bought your domain from, like GoDaddy, Squarespace, etc.

Once logged in, the records can be made in a section called “DNS settings”, or similar.

SPF Record

Find where you can add new records and select “TXT” (it might be called “Text”, “Text Record”, or something similar).

Enter the following text in the value/data field: “v=spf1 include:mailgun.org ~all”

Save your changes.

Note: if you already have an SPF record, simply add the “include:mailgun.org” before the “~all”. If you have previously added “include:talkbox.email”, replace this with mailgun.org.
You can only have one SPF record per domain.

DKIM Record

Add a new “TXT” record.

In the name/host/alias field, enter the specific value provided – (selector)._domainkey.yourdomain.com
The (selector) will look similar to “pic._domainkey” or “mx._domainkey”.
Replace (selector) with their provided value and yourdomain.com with your actual domain name.

In the value/data field, paste the DKIM key provided – this is a very long string of characters, typically 255 characters. It will look something like “k=rsa; p=MIGfMA0GCIA…IDAQAB”.
Ensure you have copied all of this correctly.

DMARC Record

Add a new “TXT” record. If you already have one for your domain, skip this step.

In the name/host/alias field, enter “_dmarc”.
The whole domain should look like “_dmarc.yourdomain.com”

In the value/data field, enter
“v=DMARC1; p=reject; rua=mailto:dmarc@yourdomain.com.”

Note: in these examples, replace “yourdomain.com” with your actual domain name. The “p=” portion can be either “none”, “quarantine” or “reject”, depending on the strictness.


DNS records are well known to take time to propagate any changes.
It is common for verification of your domain to take several hours, or even more than a day.

You can use online tools to check if your records are set up correctly. For example, MXToolbox, or search for “SPF checker” or “DKIM checker” online.

Once verified, you can create new email sender details with your custom domain. We advise sending test emails and asking the recipient/s to check if it’s marked as spam or if there are any issues with it.

Support from Common Domain/DNS Providers

GoDaddy: Add a TXT record or Add an SPF record

Squarespace: Adding custom DNS records to your Squarespace-managed domain

Shopify: Editing the DNS settings for your Shopify-managed domain

Updated on June 26, 2024

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