DKIM vs SPF: What Is the Difference?

FindMyTeam April 12, 2026

A practical explanation of DKIM and SPF, and why one is about message signing while the other is about sender authorisation.

DKIM and SPF are both email-authentication signals. That does not make them interchangeable.

SPF

SPF is about sender authorisation.

It tells receiving systems which infrastructure is meant to be allowed to send mail for the domain.

DKIM is about message signing.

It helps show whether the message was signed by the right domain and whether the signed content still validates.

Because both show up in the same mail-auth discussions, and both can affect deliverability.

But they solve different parts of the problem.

SPF is about who may send.

DKIM is about whether the message was signed in a way receivers can validate.

Stay in the same investigation track with these closely related guides.

Separate the signing layer from the policy-and-alignment layer so the two do not get collapsed together.

Understand the selector label that tells you which DKIM TXT record you are actually meant to inspect.

Separate sender authorisation from domain-level policy so the two do not get treated like the same thing.

Run the same diagnostics to follow along with the guide.

Inspect IP carriers, ASNs, and security posture in real time.

Verify WHOIS, DNS, SSL, and safety signals for any hostname.

Measure document timings, PageSpeed snapshots, and delivery overhead.