SPF checker
Enter a domain to fetch its published SPF record, break down every include and mechanism, and see whether you are within the 10 DNS lookup limit before receivers fail authentication for your form or marketing mail.
How receivers check SPF
When mail arrives, the receiving server reads the domain in the SMTP MAIL FROM envelope (and often aligns it with the visible From header under DMARC). It looks up a TXT record on that domain that starts with v=spf1, then walks each mechanism in order. Matching ip4, ip6, or a passing include: means SPF passes for that hop. The final all mechanism sets the default for everyone else.
A soft fail (~all) usually still delivers the message but may add a spam score. A hard fail (-all) tells strict receivers to reject mail from unlisted servers. Neutral ?all and permissive +all give weak or dangerous signals — fix those before you rely on SPF for production sends.
Why SPF alone is not enough
SPF breaks easily when messages are forwarded, and it only validates the envelope domain unless DMARC alignment ties it to your From address. Add DKIM so receivers can verify a cryptographic signature on each message, and publish DMARC so you get reports and a clear policy when SPF or DKIM fails. The email deliverability checker shows all three DNS pieces in one pass.
If you send contact-form notifications, list every outbound service in SPF with the SPF record generator, then confirm the live record here. Send From an address on your own domain, put the visitor in Reply-To, and route submissions through a backend built for deliverability — see form-to-email on splitforms for the pattern we recommend.
FAQ
What does ~all vs -all mean?
~all (soft fail) tells receivers to accept mail from servers not in your record but treat it as suspicious. -all (hard fail) tells them to reject it. Use ~all while you verify every sender, then move to -all when the list is complete.
What is the SPF 10 DNS lookup limit?
While checking SPF, a receiver may perform at most 10 DNS lookups. Each include:, a, mx, exists and redirect= in your record counts, and lookups inside included records count too. Over the limit, SPF returns permerror and fails. This tool estimates lookups from top-level terms only.
Can I have two SPF records?
No. Publish exactly one TXT record starting with v=spf1 on your root domain. Two SPF records make SPF invalid and receivers treat it as a fail. Merge every include and IP into a single record instead of adding another.
Do I need SPF for my contact form emails?
Yes, if notifications are sent From an address on your domain. SPF tells inboxes which servers may send as you. Use your domain in the From address with SPF, DKIM and DMARC in place, and put the visitor's address in Reply-To so you are not forging Gmail or Yahoo in From.
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Terms explained in the form glossary: SPF, DMARC, DKIM