Sender Policy Framework (SPF) is an email authentication method used to verify that an email message has been sent from a server authorised by the domain it claims to come from.
SPF works by checking the sending server's IP address against a list of approved senders published in the domain's Domain Name System (DNS) records. If the server is authorised, the SPF check passes. If not, the email may be marked as suspicious, sent to spam or rejected entirely.
The primary purpose of SPF is to prevent email spoofing. Spoofing occurs when spammers send emails that appear to come from a trusted domain. By publishing an SPF record, domain owners tell receiving mail servers which systems are allowed to send email on their behalf.
SPF is not a spam filter on its own. It does not assess content or engagement. Instead, it acts as a trust signal for inbox providers such as Google and Microsoft, helping them decide whether an email is legitimate.
For effective email delivery, SPF should be used alongside other authentication methods such as DomainKeys Identified Mail (DKIM) and Domain-based Message Authentication, Reporting and Conformance (DMARC). Together, these protocols improve sender reputation and reduce the risk of emails being blocked or diverted to spam folders.
If you send newsletters, automated emails or transactional messages, a correctly configured SPF record is essential. Without it, even legitimate emails can fail authentication checks and struggle to reach the inbox.
Businesses serious about performance and deliverability should treat SPF as a baseline requirement, not an optional extra. It is a core technical foundation of professional email marketing.
Example: After adding an SPF record to our domain, fewer emails were flagged as suspicious by inbox providers.
Need help setting up or reviewing SPF as part of a wider email strategy? Explore our Email Marketing services to see how we improve deliverability, engagement and long-term results.