Free SPF Record Checker
Find and parse a domain’s SPF TXT record, count DNS lookups, and review practical recommendations for reliable email authentication.
Common use cases
- Validate SPF after adding a new email service provider.
- Check whether an SPF record is approaching the DNS lookup limit.
- Investigate SPF failures alongside DMARC and MX configuration.
The SPF checker discovers the domain SPF TXT record, parses mechanisms and modifiers, estimates DNS-triggering lookups, and flags configurations that commonly cause permanent errors or authorize unintended senders.
Read the policy from left to right
SPF evaluates mechanisms in order until one matches. The final all mechanism defines the result for senders that matched nothing earlier; ~all is a soft failure, while -all is a hard failure.
- Publish one SPF policy record for a domain, not several competing v=spf1 records.
- Include every service that sends using the domain in the SMTP envelope sender or HELO identity.
- Remove obsolete includes before adding new senders so the policy stays understandable.
Fix lookup pressure carefully
SPF processing permits at most ten DNS-query-causing terms. Includes, redirects, a, mx, exists, and ptr can contribute; nested includes count too.
- Inventory real senders before changing the record.
- Remove unused services and avoid the deprecated ptr mechanism.
- Treat record flattening as an operational commitment because provider address ranges can change.
Standards and further reading
Diagnostic output is evidence, not a guarantee of security, deliverability, availability, or search ranking. Read the NerdTools methodology and limitations before making consequential changes.
Frequently asked questions
Why does SPF DNS lookup count matter?
SPF evaluation has a DNS lookup limit. Too many include, a, mx, ptr, or redirect mechanisms can cause SPF permerrors.
Does this modify my DNS?
No. The checker is read-only and only reports what is currently published in DNS.