SPF
Finds the record, flags missing, duplicate, +all, and ?all records, and counts DNS lookups against the limit of 10.
Free SPF, DKIM and DMARC checker for your sending domain.
Enter a domain (or any address on it). SendGuard reads its SPF, DKIM, DMARC, MX, and MTA-STS records, grades the setup, and lists each problem with the fix.
20 free checks per day, shared across SendGuard tools. Nothing is sent and no SMTP session is opened.
How it works
What this check covers.
DKIM and DMARC
Looks for DKIM keys on common selectors and reads the DMARC policy and reporting address.
MX and transport
Lists MX hosts and the mail provider, and checks MTA-STS, TLS-RPT, and BIMI records.
FAQ
Common questions
Why does SPF, DKIM, and DMARC matter for cold email?
Gmail and Yahoo require SPF or DKIM plus DMARC from bulk senders, and receivers use them to decide whether mail is really from your domain. Missing or broken records push mail to spam or get it rejected.
Why does the checker say DKIM was not found when I set it up?
DKIM keys live under a selector chosen by your mail provider. The checker tries common selectors (google, selector1, selector2, default, k1, dkim). If your provider uses a custom selector, look it up in the provider's DNS instructions.
What does the SPF lookup count mean?
SPF allows at most 10 DNS lookups (include, a, mx, ptr, exists, redirect). Above that, SPF fails with a permanent error. The checker counts top-level terms; nested includes add more.
Run this check automatically before your AI agent sends.
The SendGuard preflight API and MCP server return allow, requires_approval, delay, or block for every outbound email. The $1 Pilot includes 100 checks.
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