This DKIM checker page helps you verify domain selectors, TXT records, and signing readiness before deliverability drops.
DKIM meaning in one line
DKIM (DomainKeys Identified Mail) is an email-signing standard that lets receivers verify a message was authorized by your domain and was not altered in transit.
What is a DKIM signature?
A DKIM signature is a cryptographic header added by the sending system. The receiver uses your published public key () to verify it.
What to validate with a DKIM checker
- Selector DNS TXT record exists
- Public key syntax is valid
- Selector name matches your sending platform
- DKIM alignment supports your DMARC policy
DKIM troubleshooting flow
- Identify the selector from your ESP or SMTP provider
- Query
- Verify a valid
andkey value - Send a test email and inspect headers for
How to verify DKIM signature results in headers
Use Email header analyzer and look for:
in- selector (
) matching your intended DNS record - domain (
) aligned with your DMARC policy domain
Common DKIM problems
Wrong selector
Teams often publish one selector and send with another. Confirm the selector in message headers matches DNS.
Truncated key value
Long TXT records can be wrapped incorrectly when copied between providers. Re-check quoting and formatting.
Missing rotation process
Without key rotation, compromised keys remain valid longer than needed. Define a regular selector rotation cadence.
Related tools
Next step for production teams
Combine DKIM validation with SPF and DMARC checks in one workflow using MailSlurp authentication monitoring.