Sender Policy Framework
Sender Policy Framework (SPF) is a simple email authentication system developed to identify spoofing and impersonation. It lets receiving mail servers check whether messages sent from a given domain originated from a host authorized by the domain owner. RFC 7208 defines Sender Policy Framework.
On this page
Source content checked . English translation published 2026-10-27.
In business automation
SPF tells a mail server which hosts are allowed to send on behalf of a domain. In automation, it affects whether system messages, invoices, and reminders reach the inbox or are blocked as spoofed mail.
Examples
These examples illustrate a possible workflow. Adapt the connections and rules to your own systems.
Send an invoice from the business domain
The process sends an invoice through a mail provider. DNS specifies that only the provider's hosts may send from that domain. A message from another server using the same sender name fails the SPF check and is not treated as legitimate.
Relevant tools
- Resend
- Connecting a domain requires an SPF record that points to the sending servers. Without it, messages may be blocked even when their content is valid.
What to check
- An overly broad SPF record, such as one using plus all, almost completely disables the protection.