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Verify your DKIM record is set up correctly. Enter your domain and selector to check your email authentication and improve deliverability.
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What is DKIM?
DKIM (DomainKeys Identified Mail) is an email authentication protocol that lets you digitally sign your outgoing emails. When you send an email, your mail server adds an encrypted signature to the message header. The receiving server then looks up your public key in DNS and uses it to verify the signature.
If the signature is valid, the recipient knows the email genuinely came from your domain and was not tampered with during delivery. This builds trust with email providers and helps your messages reach the inbox instead of the spam folder.
Why DKIM matters for email deliverability
Prevents spoofing
Without DKIM, anyone can send emails that appear to come from your domain. Phishers exploit this to trick your customers. DKIM makes spoofed emails fail authentication, protecting your brand reputation.
Improves inbox placement
Gmail, Microsoft, Yahoo, and other major providers check DKIM signatures when deciding where to deliver your email. Valid DKIM is a positive trust signal that helps your emails land in the inbox.
Required for DMARC
DMARC (Domain-based Message Authentication) relies on DKIM and SPF. Without DKIM in place, you cannot fully implement DMARC, which is now required by Google and Yahoo for bulk senders.
Survives forwarding
Unlike SPF, DKIM signatures survive email forwarding because the signature is attached to the message itself, not tied to the sending server's IP address.
Understanding DKIM selectors
A DKIM selector is a unique identifier that points to a specific public key in your DNS. The full DNS record is located at selector._domainkey.yourdomain.com. For example, if your selector is "google" and your domain is "example.com", the record is at google._domainkey.example.com.
Different email services use different selectors. Here are some common ones:
- Google Workspace:
google - Microsoft 365:
selector1,selector2 - Mailchimp:
k1 - SendGrid:
s1,s2 - Custom/Default:
default,dkim
How to fix common DKIM issues
DKIM record not found
Make sure you are using the correct selector name from your email provider. Check that the TXT record was added at the right location (selector._domainkey.yourdomain.com) and that DNS has had time to propagate (up to 48 hours).
Invalid or missing public key
The record must contain a p= parameter with your public key. If the key is empty or malformed, re-copy the exact value from your email provider's dashboard. Do not add extra spaces or line breaks.
Weak key length
If your key is less than 2048 bits, consider rotating to a stronger key. Contact your email provider to generate a new 2048-bit key, then update the DNS record.
DKIM, SPF, and DMARC: the complete picture
DKIM is one part of a three-layer email authentication system. SPF specifies which servers can send email for your domain. DKIM proves the email was not altered. DMARC ties them together and tells receivers what to do when emails fail authentication.
For the best deliverability and security, you should have all three configured. Use our SPF Record Generator to create your SPF record, and our DMARC Record Generator to create your DMARC policy.
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Try SendScale FreeFrequently Asked Questions
DKIM (DomainKeys Identified Mail) is an email authentication method that adds a digital signature to your outgoing emails. The signature is created using a private key on your mail server and verified using a public key published in your DNS. This proves that emails genuinely came from your domain and were not altered in transit.