Free tool
Check your email authentication
Enter a domain and see its SPF, DKIM and DMARC records, plus the SPF lookup count that quietly breaks sending once it passes 10. Runs in your browser. Nothing is stored and no account is needed.
Know your DKIM selector? Add it
The part before ._domainkey in the
record your provider gave you.
Common questions
- What is SPF?
- A DNS record listing the servers allowed to send email as your domain. Receivers check the sending server against it. A domain may publish exactly one SPF record.
- What is DKIM?
- A cryptographic signature added to every message, verified against a public key you publish in DNS. It proves the message was not altered in transit.
- What is DMARC?
- The policy that ties SPF and DKIM together. It tells receivers what to do when a check fails, and sends you reports about it. Gmail and Yahoo require it from bulk senders.
- Why does the checker say SPF passes but my mail still fails DMARC?
- Alignment. DMARC does not only check that SPF or DKIM passed, it checks that they passed for the domain in your From header. If your provider sends with its own Return-Path, SPF passes for the provider and not for you, and DMARC fails.
- Why can it not always find my DKIM record?
- DKIM selectors cannot be listed from DNS, so any checker has to guess them. This one probes the defaults the major providers use. A miss means we could not find one, not that you do not have one.