GoLeadX
Sign in with Google
Deliverability

SPF

SPF is a DNS record listing which servers may send email for your domain. Receiving servers check it to see whether a message claiming to come from you actually came from a server you authorised.

It is one line of DNS and the first of the three records mailbox providers look for. A domain without it is treated as unauthenticated, and since 2024 both Google and Yahoo have enforced authentication requirements strictly enough that unauthenticated bulk mail is often rejected outright rather than filtered.

The common mistakes are structural rather than typographical: publishing two SPF records instead of one, which invalidates both, and exceeding the ten-lookup limit by chaining an include for every tool that sends on your behalf.

Goes deeper: Why Your Cold Emails Land in Spam

Related terms

DKIM
DKIM adds a cryptographic signature to every message you send, which the receiving server checks against a public key in your DNS. It proves the message came from your domain and was not altered on the way.
DMARC
DMARC ties SPF and DKIM together: it tells receiving servers what to do when a message claiming to be from your domain fails those checks, and asks them to report back on what they saw.
Deliverability
Deliverability is whether your email reaches the inbox rather than the spam folder or nowhere at all. It is decided by sending reputation, authentication and list quality — not by your copy.
Sender reputation
Sender reputation is the score mailbox providers keep on your domain and sending IP, based on how recipients react to your mail. It decides whether your next message reaches the inbox.