What is an SPF Record?
SPF (Sender Policy Framework) is an email authentication method that allows domain owners to specify which mail servers are permitted to send email on behalf of their domain. It's implemented as a DNS TXT record that receiving mail servers check during delivery.
When a receiving server gets an email claiming to be from @example.com, it looks up the SPF record for example.com and checks whether the sending server's IP address is listed. If it's not authorized, the email can be rejected or marked as suspicious.
SPF Record Syntax
v=spf1 include:_spf.google.com include:sendgrid.net ip4:203.0.113.0/24 -all
v=spf1— Version identifier (required).include:— Authorize another domain's SPF record (e.g., Google Workspace, SendGrid).ip4:/ip6:— Authorize specific IP addresses or ranges.-all— Hard fail: reject emails from unlisted servers.~allis a soft fail (mark but don't reject).
Why SPF Matters
Without SPF, anyone can send email that appears to come from your domain (email spoofing). SPF is one of three pillars of email authentication, alongside DKIM and DMARC. Together, they protect your domain from being used in phishing attacks and improve your email deliverability.
Validate your SPF record with Mailchk's free SPF Checker tool.