DomainKeys Identified Mail (DKIM)

What is DomainKeys Identified Mail (DKIM)?

DKIM (DomainKeys Identified Mail) is an email authentication method that adds a digital signature to messages, letting receivers verify they are genuine.

DKIM allows the receiving mail server to confirm that an email really was sent and authorized by the owner of the sending domain, and that it was not altered in transit. It works alongside SPF and DMARC as one of the three main email authentication standards.

How does DKIM work?

DKIM uses a pair of cryptographic keys. The sending server signs each outgoing message with a private key, adding a special header to the email. The matching public key is published as a TXT record in the sending domain's DNS. The receiving server looks up that public key and uses it to verify the signature, confirming the message is authentic and unmodified.

Why does DKIM matter?

Modern email providers such as Gmail and Outlook increasingly require correct DKIM (along with SPF and DMARC) before they will reliably accept email. Without it, your messages are far more likely to be flagged as spam or rejected outright.

DKIM and MIDAS

When your MIDAS booking system sends booking confirmations and reminders from your own domain, configuring DKIM helps ensure those emails reach the inbox rather than the spam folder. DKIM works together with SPF and DMARC to give your booking emails the best possible deliverability.