SPF Record Builder and Inspector
Build and inspect SPF records locally with mechanism explanations, lookup-count guidance, and copyable TXT output.
Build a new SPF TXT value or inspect an existing one before you publish a sender policy. Work stays in your browser: this tool does not query DNS, contact mail providers, upload domains, or verify whether a referenced include or redirect record exists.
Use redirect only when another domain should supply the whole fallback policy.
How it works
Sender Policy Framework records are DNS TXT values that list which hosts or provider policies may send mail for a domain. This builder orders common mechanisms, formats a copyable v=spf1 value, and explains the effect of includes, redirects, IP ranges, MX, A, exists, and all results.
The lookup estimator counts SPF terms that can require DNS work: include, a, mx, ptr, exists, and redirect. SPF evaluation has a 10-lookup limit, and nested includes may add more lookups than are visible in one record, so treat the count as a local review aid rather than a live DNS audit.
Use redirect when another domain should provide the fallback SPF policy. Use include when you want to authorize senders that pass another domain's SPF policy while keeping the rest of your local record. Publish only one SPF TXT record per domain and review provider-specific instructions before changing mail authentication.
Related tools
Use the DNS Record Builder when you need a generic TXT record wrapper, the DNS Zone File Validator when reviewing zone-file snippets, and the Email Header Parser when checking authentication results from a received message.
