Step 1
Enter the domain and selector
Type the sending domain and the DKIM selector your provider uses. The checker looks up selector._domainkey.yourdomain.com.
DNS over HTTPS
Free DKIM Checker
A DKIM checker looks up the DNS TXT record for your selector and verifies that the domain publishes a valid DKIM public key. It helps you confirm record format, key strength, and selector health before DNS mistakes damage deliverability.
This tool queries Google DNS and Cloudflare DNS directly from your browser. If you need to inspect a specific message's DKIM verdict, pair it with the Email Header Analyzer. For SPF alongside DKIM, use the SPF Record Checker. Want this automated on every inbound email? MailParse captures authentication results automatically.
How to check a DKIM record
Step 2
Run the DNS lookup
The page queries Cloudflare DNS and Google DNS directly from your browser using DNS over HTTPS, then collects TXT answers for the selector.
Step 3
Review the parsed record and fix issues
Use the pass, warning, and failure checks to confirm the selector exists, the record starts with v=DKIM1, the public key is present, and the key strength is adequate.
Frequently asked questions
What is a DKIM checker?
A DKIM checker looks up the DNS TXT record for a selector under _domainkey and validates that the record has a usable DKIM public key, expected tags, and a safe key length.
What is a DKIM selector?
A selector is the label before _domainkey in DNS. Mail providers use selectors like google, k1, or selector1 so you can rotate keys without replacing every DKIM record at once.
What key length should a DKIM record use?
A 2048-bit RSA key is the safest default for DKIM today. A 1024-bit key may still work with some providers but is weaker, while Ed25519 uses a smaller modern key format when supported.
Why can DKIM still fail even when the record exists?
DKIM can fail if the sending service signs with a different selector, the DNS record is stale, headers are modified in transit, or the From domain is not aligned with the signature domain.
Can this tool verify a message's DKIM signature?
This page validates the DNS record behind a selector. To inspect a specific email's DKIM verdict or Authentication-Results header, use MailParse's Email Header Analyzer.