DKIM record checker
Free DKIM record checker
Check whether your DKIM signing is set up. We probe the common DKIM selectors automatically, and you can enter your own selector if you know it. We also check SPF and DMARC. No signup.
How DKIM works
DKIM (DomainKeys Identified Mail) adds a cryptographic signature to every message you send. Your mail server signs each message with a private key, and receivers fetch the matching public key from your DNS to confirm the message really came from your domain and was not altered in transit.
The public key lives at a special name built from a selector: selector._domainkey.yourdomain. A selector is just a short label, and a domain can publish several (often one per sending service). Each signed message names the selector it used so receivers know which key to look up.
This is why an honest DKIM checker can say not detected but never missing. DNS does not allow listing the selectors a domain uses, so any checker has to guess from a list of common names. If your provider uses a custom selector (Amazon SES, for example, uses random tokens), it will not be on that list, and that is not the same as having no DKIM.
To check yours exactly, open an email you sent, view the raw headers, find the DKIM-Signature line, and copy the value after the s= tag. That is your selector. Enter it in the optional selector field on the checker above and run it again.
SPF
SPF lists which mail servers are allowed to send for your domain. Receiving servers check it to spot forgeries from servers you never authorized.
DMARC
DMARC ties SPF and DKIM together and tells inbox providers what to do with mail that fails: monitor it, send it to spam, or reject it.
Looking for something specific? Check your SPF, DKIM, or DMARC record.
Keeping SPF, DKIM, and DMARC healthy is the part that quietly eats your time, and the part that decides whether your newsletter lands in the inbox or the spam folder. Yellaro handles all of it for you: managed Listmonk hosting with sending and deliverability included. See how it works or read why it matters.
Common questions
- What is a DKIM selector?
- A selector is a short label that points to one specific DKIM public key in your DNS. A domain can have several keys, often one per sending service, and each lives at <selector>._domainkey.yourdomain. The selector is included in every signed message so receivers know which key to look up.
- Why does it say DKIM was not detected?
- DNS does not let anyone list every selector a domain uses, so the checker probes the common ones. Not detected means we did not find DKIM at those names. It does not mean DKIM is missing: many providers (Amazon SES, for example) use a custom selector we cannot guess. Enter your selector above to check it exactly.
- How do I find my DKIM selector?
- Open an email you sent to yourself or a colleague and view the original or the raw headers. Find the DKIM-Signature header and look for the s= tag. The value after s= is your selector. Paste it into the selector field above and run the check again for an exact result.
- Is this checker free?
- Yes, completely free and no signup. Check as many domains as you like.