What is SPF flattening?
Recursively resolves all include:, a:, mx:, and redirect= mechanisms into IP addresses.
SPF allows only 10 DNS lookups. Flattening replaces lookup-causing mechanisms with ip4: and ip6: entries.
Get a ready-to-publish flattened record. If it exceeds the length limit, we split it for you automatically.
See the complete include tree, every resolved IP, DNS lookup counts, and warnings about your SPF configuration.
Why flatten your SPF?
Modern email sending often involves multiple providers—Google Workspace, Microsoft 365, Mailchimp, Salesforce, and more. Each include: in your SPF record triggers one or more DNS lookups. When you exceed the 10-lookup limit defined in RFC 7208, receiving mail servers may return a permerror, causing your emails to fail SPF authentication.
Flattening replaces those nested include: chains with the actual IP addresses they resolve to, reducing your lookup count to zero while preserving exactly the same authorisation policy.
Note: Flattened records are a point-in-time snapshot. If your email providers change their IPs, you will need to re-flatten. Consider automating this process for production use.