Pro move: type dmarc:yourdomain.com or blacklist:1.2.3.4 straight into the box — it switches tools for you.
About this tool. SPF is a DNS record listing every service allowed to send email as your domain. Broken or duplicate SPF gets your mail junked. This check validates the record, counts the 10-lookup limit that silently breaks SPF, and names the senders it recognizes.
How to read your spf record checker results
SPF is a single DNS TXT record listing every server allowed to send mail as your domain. We decode each mechanism in plain English.
Watch the DNS lookup count. SPF is limited to 10 lookups. Go over and it fails, no matter how correct the rest is.
The ending matters: -all is a hard fail (strict), ~all is a soft fail (lenient), and +all is dangerous and should never be used.
Common problems and how to fix them
SPF passes some places and fails others
You likely exceed the 10-lookup limit or have two SPF records. Flatten includes you do not need and merge into one record.
A vendor's mail is being rejected
Add that vendor's include or IP to your single SPF record. Do not create a second SPF record.
Common questions.What is an SPF record?
A DNS TXT record that lists which mail servers are authorized to send email using your domain.
What is the SPF 10-lookup limit?
SPF may trigger at most 10 DNS lookups while evaluating. Exceeding it causes a permerror and SPF fails, so keep includes lean.
Should I use -all or ~all?
-all (hard fail) is stronger and preferred once you are confident every legitimate sender is listed. ~all (soft fail) is a safer starting point while you verify.