Free tool

SPF Record Checker

Validate any domain's SPF record. Parses every mechanism, counts your DNS lookups, flags the breakage patterns we see every day.

What this tool actually does

It queries your domain for TXT records, identifies the one that starts with v=spf1, breaks it apart into mechanisms, counts the DNS lookups each mechanism would cost, and reports the final all qualifier. If you have multiple SPF records (which is a violation), we flag that too.

The two things to watch

DNS lookup count over 10 means your record returns permerror, treated as no SPF by most receivers. Wrong all qualifier (especially +all) means your record either does nothing or actively authorizes spoofing. Both are silent failures, your mail looks like it should authenticate but doesn't.

What's not in this tool (yet)

Recursive include walking. We count top-level mechanisms. To see how many lookups a fully-recursive evaluation would cost, sign up for continuous monitoring, we re-check your SPF hourly and flag the drift.

FAQ

How does the SPF checker work?

We resolve the TXT records for your domain, parse every v=spf1 record we find, walk through each mechanism, count DNS lookups, and identify the all-qualifier. It's the same engine our continuous monitoring uses.

Why is the DNS lookup count important?

RFC 7208 caps SPF evaluations at 10 DNS lookups. Each include:, a, mx, ptr, exists, or redirect counts as one. Exceed 10 and your SPF returns permerror, equivalent to no SPF for most receivers.

What does the "all" qualifier mean?

-all (hardfail) means "reject any sender not on this list." ~all (softfail) means "mark suspicious but accept." +all means "everyone is allowed", a critical security mistake. ?all is "neutral", pointless to publish.

Do you check nested includes?

For lookup counting, we count top-level mechanisms (matching the RFC 7208 rules). For pure validation, we don't recursively walk every include's record, that would expose you to multi-second checks. Use our continuous monitoring if you want recursive validation.

SPF. Complete Guide

Full reference covering syntax, the 10-lookup limit, and deployment.

DMARC Analyzer

Verify your DMARC policy and reporting setup.