SPF Record Checker
No signup. No limits. Same continuous check we run on every managed mailbox.
What is an SPF record?
SPF (Sender Policy Framework) is a DNS TXT record listing which mail servers can send mail for your domain. Receivers check it on every message; unlisted senders fail authentication.
How to read your result
~all = soft fail. -all = hard fail. +all is dangerous and should never appear. The 10-lookup limit is the most common silent killer — each include: counts and they chain.
Common errors that kill deliverability
Multiple SPF records (forbidden by RFC), too many includes (over 10 lookups), missing sequencer include, stray syntax characters.
Correct examples
Google Workspace: v=spf1 include:_spf.google.com ~all
Microsoft 365: v=spf1 include:spf.protection.outlook.com ~all
Common questions
CLAYINBOX runs this check continuously on every domain it manages — automatically.