SPF, DKIM and DMARC checker

Enter a domain to check its SPF, DKIM and DMARC records and MX setup. Each result says what is wrong in plain English and gives the exact record to fix it.

What this checker looks at

• SPF

  Finds the v=spf1 TXT record at your root domain, flags duplicates and weak endings, and counts DNS lookups against the 10-lookup limit in RFC 7208.

• DKIM

  Looks up the public key at selector._domainkey for your selector or a list of common ones, and reports the RSA key size.

• DMARC

  Reads the policy at _dmarc, explains p=none, quarantine and reject, and checks that off-domain report addresses are authorized.

• MX

  Detects Google Workspace or Microsoft 365 from your MX records and checks that SPF includes the matching provider.

Guides

• SPF, DKIM and DMARC setup

  The three records, in order, with example values for Google Workspace and Microsoft 365.

• DMARC policy: none vs quarantine vs reject

  What each policy does and how to move to enforcement without blocking your own mail.

• Cold email domain setup

  Secondary domains, inboxes per domain, warmup windows and daily send benchmarks.

How it works

Your browser sends DNS queries straight to public DNS-over-HTTPS resolvers (Cloudflare, with Google Public DNS as a fallback). The results are analyzed on your device. Nothing is sent to this site or stored. More about the checker.