Using a custom domain for email sending

Note: This is an advanced article. If you aren't comfortable customizing your DNS records (or don't know what they are) you shouldn't proceed. You can also hire a Certified Expert to help you get set up! 

A custom sending domain allows you to send messages via your own domain, rather than ConvertKit's. To set one up, it requires a couple things:

Understanding SPF & DKIM

Your deliverability is based on two things: the reputation of your email marketing provider and your own domain reputation.

One thing we offer is the ability to set up a custom sending domain, which allows you to set up authentication records with your webhost. This tells email providers like Gmail and Outlook that you are a real business, and you have given ConvertKit permission to send on your behalf.

SPF stands for Sender Policy Framework. It was specifically created to protect against sender address forgery--spammers pretending to send emails as you. An SPF record in your DNS Settings gives email providers something to check, to make sure the emails are really coming from you. Read more about SPF here.

DKIM stands for Domainkeys Identified Mail. It too was designed to prevent domain spoofing, or someone pretending to send from your email domain, when they really aren't. DKIM uses cryptographic authentication, which means the records we generate will be unique to you and your domain. Read more about DKIM here.

These records are not required, but can improve your deliverability to your subscribers!

MX Records

If you're familiar with MX records, you may know that they are related to receiving emails to your domain. MX records are also used by smaller email providers (often outside the US) for the same authentication reasons as SPF and DKIM.

Do I need to set up a subdomain?

Short answer: no. 

We ask you to set up your SPF, DKIM & MX records on a subdomain of your domain, instead of the top level domain, but you don't actually need to create a subdomain itself. All you need to make sure is that your hostname for each record includes "ck." This prevents your authentication records from interfering with your domain, but it doesn't not require the extra work of setting up a separate subdomain. This is especially important for MX records, as any MX records set up on your top level domain would prevent emails from reaching your inbox.

If your DNS provider is suggesting you create any A or CNAME records, or set up a totally separate subdomain, stop. You don't need those. Just copy and paste the information we give you into the right fields and you're all set! 

I want a custom sending domain! 

Here's what you need to do!

  1. Send an email to that tells us your domain name and ask for custom domain records. Do not make any changes or additions to your DNS settings before you contact us! 
  2. We'll reply with the values to add to your DNS records. They'll look something like this:

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Configuring your records

Once you get that information you need to configure your records with your DNS. This is typically done through your host or domain registrar (,,, etc.). Instructions here may vary (check with your host support if you get stuck); however, these are the basic steps:

  1. Scroll to the TXT section within the DNS editor.
  2. Create a new TXT record by clicking the "add" button.
  3. Set hostname to the hostname value we give you, generally "" or just "ck" (dependent on the host). 
  4. Fill the TXT Value field with your SPF record ("v=spf1 ~all").
  5. Save.

You'll then do the same thing for your domain key TXT record (we'll send it to you since it's unique to your subdomain).

MX records may be set up similarly, depending on your host. The most important things to note are:

  • The record type will be "MX."
  • The hostname will be "" or just "ck."
  • The priority will be 10.
  • You will need to set up two MX records, and

Write back to ConvertKit support

Once you're done with that send us an email to let us know. We'll do some work on our side to configure your email to send through the new domain. After that you'll be good to go!


And if you want to learn how to craft your email content with Deliverability in mind, check out " How to Beat the Spam Filters at Their Own Game" on our blog!

Want help with this? 

Melissa Thorpe is a Certified ConvertKit Expert, and would love to help get this done for you! She would love to hear from you. 

Click here to reach her