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DKIM Record Checker

Validate your domain's DKIM configuration. Verify email signing is working correctly and detect issues that impact deliverability.

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What is DKIM?

DKIM (DomainKeys Identified Mail) is an email authentication method that uses cryptographic signatures to verify that an email was sent by an authorized server and wasn't modified during delivery.

Think of DKIM as a digital seal on your emails. When your mail server sends an email, it attaches a unique signature created using a private key. The receiving server then verifies this signature using a public key stored in your DNS records. If the signature is valid, the email is confirmed as authentic and unaltered.

DKIM works alongside SPF and DMARC to provide comprehensive email authentication. While SPF validates the sending server, DKIM validates the message itself — and DMARC ties them both together with a policy.

Frequently Asked Questions

What is DKIM?
DKIM (DomainKeys Identified Mail) is an email authentication protocol that allows the sender to digitally sign outgoing emails. The receiving server can then verify the signature using a public key published in the sender's DNS records. This proves the email hasn't been tampered with in transit and confirms it was authorized by the domain owner.
How does DKIM work?
When you send an email, your mail server creates a cryptographic hash of certain email headers and the body, then signs it with a private key. This signature is added as a DKIM-Signature header. The receiving server looks up your public key in DNS (at selector._domainkey.yourdomain.com) and uses it to verify the signature. If the signature matches, the email passes DKIM authentication.
What is a DKIM selector?
A DKIM selector is a string used to locate your DKIM public key in DNS. Each email service you use (Gmail, SendGrid, Mailchimp, etc.) typically has its own selector. For example, Google Workspace uses selectors like "google" or "google2", making the full DNS lookup "google._domainkey.yourdomain.com". You can have multiple selectors for different sending services.
Why is DKIM important for email deliverability?
DKIM is crucial because it: (1) proves your emails haven't been modified in transit, (2) confirms the email was authorized by your domain, (3) is required for DMARC alignment, (4) improves your domain reputation with email providers, and (5) is now required by major providers like Gmail and Yahoo for bulk senders. Without DKIM, your emails are more likely to be flagged as spam.
How do I set up DKIM?
DKIM setup varies by email provider. Generally: (1) Generate a DKIM key pair in your email service's admin panel. (2) Add the public key as a TXT or CNAME record in your DNS at the location specified by your provider (usually selector._domainkey.yourdomain.com). (3) Enable DKIM signing in your email service. (4) Test by sending an email and checking the DKIM-Signature header.

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