Free DKIM Checker
Check whether your domain publishes a DKIM key.
This DKIM checker probes the common selectors used by major providers (Google, Microsoft 365, Zoho, SendGrid, Amazon SES and more) to see whether your domain publishes a DKIM public key — shown alongside your SPF and DMARC status for the complete email-authentication picture.
DKIM (DomainKeys Identified Mail) adds a cryptographic signature to your outgoing email so receivers can verify it wasn't altered and truly came from your domain. Along with SPF, it's one of the two checks DMARC uses to decide whether mail is legitimate.
Because providers use different selector names, a custom setup may not be detected here — the paid plan lets you specify your exact selector and monitors it continuously across all your domains.
Frequently asked questions
- What is a DKIM selector?
- A selector is a label that points to a specific DKIM public key in your DNS, at selector._domainkey.yourdomain.com. Providers each use their own — for example Google uses 'google'.
- Why does the check say no DKIM found when I have it?
- We test common selectors only. If your provider uses a custom selector we may not find it automatically. Confirm your selector with your email provider.
- Do I need DKIM as well as SPF?
- Yes. DMARC passes when either SPF or DKIM aligns, but having both — especially DKIM, which survives forwarding — gives the most reliable deliverability and protection.