Free SPF Checker
Paste in a domain to check its SPF record for syntax errors, too many DNS lookups, and a fail policy that's leaving you exposed.
Runs a live DNS lookup against the domain you enter — connect it in CleanMarc for continuous monitoring and 1-click fixes.
Enter a domain above and click Check SPF to see a sample report.
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Published record
This is a sample report. CleanMarc runs checks like this continuously and pushes the corrected record for you.
Get 1-click fixesWhat the checker looks for
SPF looks simple until a record silently breaks. Here's every check this tool — and CleanMarc's continuous monitoring — runs against your domain.
Record lookup
Confirms a TXT record starting with v=spf1 exists for the domain and that DNS resolves cleanly.
Duplicate records
Flags domains publishing more than one SPF record — RFC 7208 allows only one, and a second silently breaks authentication.
DNS lookup budget
Counts every include, a, mx, ptr, and exists mechanism against the hard 10-lookup limit so you don't fail SPF from being too permissive.
Fail policy strength
Checks whether the record ends in a hard fail (-all), soft fail (~all), or the wide-open +all, and recommends the safest fit.
Syntax validation
Catches malformed mechanisms, unknown modifiers, and typos that cause receiving servers to treat the record as a permerror.
Known ESP coverage
Cross-references includes against common senders like Google Workspace, Klaviyo, and Mailchimp so you can spot a missing sender fast.
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