By the team at MailTester Ninja, a real-time email verification API that stores nothing.
76.9% of domains publish an SPF record. But SPF only bites if it ends in -all (hardfail). Here's how SPF publishers actually terminate their record:
-
~all, 50.2% -
-all, 44.8% -
noneall, 2.6% -
?all, 2.4% -
+all, 0%
~all (softfail, 50.2%) tells receivers "this probably isn't authorized… but deliver it anyway." -all (hardfail, 44.8%) tells them to reject it. Softfail is the safe default that never gets tightened, which means most domains publish SPF that a spoofer can walk straight past. If you own the domain and every legitimate sender is listed, -all is where you want to be.
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Source: MailTester Ninja's open Email Infrastructure Index, a live DNS scan of 50,000 of the world's most-linked domains, updated daily, aggregate only. Free to cite under CC BY 4.0. Snapshot: Mon, 17 Aug 2026 04:18:29 GMT.
