Free SPF Record Checker
An SPF (Sender Policy Framework) record is a DNS TXT record that specifies which mail servers are authorized to send email for your domain. Paste your SPF record below to validate it for syntax errors, DNS lookup limits, and best practices.
Frequently Asked Questions
What is an SPF record?
SPF (Sender Policy Framework) is a DNS TXT record that lists which mail servers are authorized to send email on behalf of your domain. Receiving servers check the SPF record to verify the sender.
What is the 10 DNS lookup limit?
RFC 7208 limits SPF evaluation to 10 DNS lookups. Mechanisms like "include", "a", "mx", "ptr", "exists", and "redirect" each count as one lookup. Exceeding this causes a permanent error (permerror).
What is the difference between ~all and -all?
"~all" (softfail) marks messages from unauthorized senders but still delivers them — useful during rollout. "-all" (hardfail) instructs receivers to reject unauthorized messages outright.
Why is the ptr mechanism deprecated?
The ptr mechanism requires a reverse DNS lookup for every connecting IP, which is slow, unreliable, and puts load on the DNS system. RFC 7208 recommends using ip4, ip6, or a mechanisms instead.
How do I fix too many DNS lookups?
Flatten your SPF record by replacing "include" mechanisms with the actual ip4/ip6 addresses they resolve to. Tools that auto-flatten SPF can help maintain this over time.