What is SPF in email?

Sender Policy Framework — a DNS record that lists the servers allowed to send mail for your domain, so receivers can detect unauthorised senders.

Is SPF enough on its own?

No. SPF validates the envelope sender and breaks on forwarding. It needs DKIM and DMARC alongside it, which bulk-sender rules now require.

How do I add a sending service to SPF?

Add the provider's specified include or IP to your domain's SPF TXT record, staying under the ten-lookup limit, then verify it resolves before sending.

Growth Marketing Glossary

SPF

SPFnoun

The guest list for your domain's mail — receivers check it before trusting the envelope.

Schematic — SPF authorising sending servers

Stands for: Sender Policy Framework
Lives in: a DNS TXT record
Authorises: sending servers by IP
Pairs with: DKIM and DMARC

Forms & parts of speech

SPF · noun

A DNS record listing servers authorised to send for a domain.

"Add the vendor's include to your SPF record before sending through them."

What SPF does

SPF is a DNS record that lists which mail servers are allowed to send email on behalf of your domain. When a receiving server gets a message, it checks the sender's IP against that list.

If the sending server is authorised, the message passes SPF. If it is not, the check fails — a signal that the mail may be spoofed. SPF protects the envelope sender, the address servers actually talk to.

Its limits and its partners

SPF alone is incomplete. It validates the envelope sender, not the from address a reader sees, and it breaks when mail is forwarded. That is why it is one leg of a three-part stack, not the whole answer.

DKIM adds a cryptographic signature, and DMARC ties SPF and DKIM to the visible from domain with a policy. Google and Yahoo's 2024 rules require bulk senders to have all three set up correctly.

Worked example. Suppose a brand starts sending through a new email platform. Until the platform's servers are added to the domain's SPF record, receiving servers see mail from an unauthorised IP, SPF fails, and deliverability suffers. Adding the platform's SPF include fixes the check.

But SPF is only the first leg — without DKIM and DMARC alongside it, the domain still falls short of the bulk-sender requirements that govern Gmail and Yahoo delivery.

Failure modes to watch. Relying on SPF alone for authentication; exceeding the ten-DNS-lookup limit so SPF silently fails; and forgetting to add a new sending vendor to the record before launching through it.

Benchmarks

SPF is a pass or fail check, not a benchmarked metric. The figure that matters is full authentication coverage across SPF, DKIM, and DMARC.

Record type

DNS TXT

Lookup limit

Required by

Google/Yahoo 2024

Ranges are illustrative; every published figure is cited from a named public source or labelled “RGM analysis.”

Synonyms & antonyms

Synonyms

sender policy framework

Antonyms

spoofing

Usage trends

Search interest for this term over the last five years:

View interest-over-time on Google Trends →

Common questions

What is SPF in email?: Sender Policy Framework — a DNS record that lists the servers allowed to send mail for your domain, so receivers can detect unauthorised senders.
Is SPF enough on its own?: No. SPF validates the envelope sender and breaks on forwarding. It needs DKIM and DMARC alongside it, which bulk-sender rules now require.
How do I add a sending service to SPF?: Add the provider's specified include or IP to your domain's SPF TXT record, staying under the ten-lookup limit, then verify it resolves before sending.

Related tools & calculators

Resources & people to follow

referenceGoogle & Yahoo bulk-sender requirements (2024)
referenceRFC 7208 — Sender Policy Framework

Curated, non-competitor resources verified per term.

Sources

trendsGoogle Trends — "spf email"

SPF