Learn what email authentication is, why it's important, and how to set it up for the domains you use to send email from Kartra.

Email authentication helps email service providers confirm that your messages are legitimate and sent by you, rather than spammers pretending to be you. 

Every domain you use as a “send-from” address in Kartra must be authenticated. 

For example:

  • Sending from info@yourbrand.com → authenticate yourbrand.com
  • Sending from team@yourcourses.co → authenticate yourcourses.co

Required authentication for Kartra

Kartra requires DKIM for every domain you use as a “send-from” domain. Without DKIM, your messages may fail to send or be rejected by email service providers.

DKIM (DomainKeys Identified Mail)

  • Confirms your emails were digitally signed by your domain
  • Essential for deliverability
  • Required by KartraMail and also required when sending through a 3rd-party SMTP

Kartra’s automatic setup tool handles DKIM for you when your domain host is supported.

Recommended email authentication

Additional authentication records can help improve deliverability and trust. These are not required in order to send emails through KartraMail, but we do recommend them. 

SPF (Sender Policy Framework) 

  • Lists services allowed to send email on behalf of your domain
  • Helps prevent spoofing
  • Required only for 3rd-party SMTPs
  • If you use KartraMail: Kartra's SPF is already included on the sending gateway, so you don’t add SPF yourself

Learn more about SPF.

DMARC (Domain-based Message Authentication, Reporting, and Conformance)

  • Tells email providers how to handle messages that fail DKIM or SPF
  • Helps protect your brand
  • Is optional, but highly encouraged for stronger authentication and reporting

Learn more about setting up DMARC.

How authentication works in Kartra

Email authentication requires adding DNS records at your domain host. Kartra supports two setup paths:

Automatic setup (recommended)

If your domain provider is supported, Kartra can configure DKIM automatically. This is the fastest and most reliable setup method.

Once this step is completed:

  • DKIM is created for you
  • SPF is handled automatically if you use KartraMail
  • You can optionally add DMARC for reporting and protection

Learn how to set up DKIM automatically.

Manual setup

If your domain host does not support automatic setup, Kartra will display the exact DKIM DNS values you need to add manually.

Learn how to set up DKIM manually.

What if you send email through a 3rd party SMTP?

If you use a third-party SMTP provider:

  • DKIM is created for your SMTP account, not in Kartra
  • Your SPF record should include your SMTP provider’s sending servers
  • DMARC can be added at your discretion for policy and reporting