SPF: Sender Policy Framework
SPF is a DNS record that lists which servers are allowed to send email for a domain.
How it works
A receiving server compares the connecting server's address with the sender domain's SPF record and notes a pass, fail or something in between. A record is limited to ten DNS lookups, so large senders have to keep it tidy.
SPF on its own does not stop a forged "From" address that people see. That is what DMARC adds.
To read a domain's policy, fetch its TXT records and find the one that starts with v=spf1. The ending says what to do with other senders: -all asks receivers to reject them, ~all marks them as suspicious, and ?all takes no position. A domain with no SPF record, or with two of them, has not set it up correctly.
Related LookValid products
| Product | Credits | Docs |
|---|---|---|
| Email Domain Check | 1 credit per address checked | API docs |
New to the API? Start with the quickstart or the API reference. Agents can call the same lookups through the MCP server.