SPF

What is SPF?

Sender Policy Framework

Sender Policy Framework (SPF) is a DNS TXT record that lists which IP addresses and services can send email using your domain as the From address. Receiving mail servers check the SPF record — if the sending IP is not on the list, the message fails SPF.

In more detail

SPF is one of three records (SPF, DKIM, DMARC) that together authenticate outgoing email. SPF covers the envelope (return path); DKIM signs the headers and body; DMARC sets the policy.

The record starts with `v=spf1` and lists allowed senders. Common entries include `include:_spf.google.com` (Google Workspace), `include:_spf.resend.com` (Resend), `include:mailgun.org` (Mailgun). It ends with `~all` (soft fail) or `-all` (hard fail).

SPF record for Google Workspace + Resend
v=spf1 include:_spf.google.com include:_spf.resend.com ~all

Why this matters

Why builders care

Every AI-built SaaS sends transactional email (signups, password resets, receipts). Without SPF, those emails go to spam on Gmail and Outlook. Adding SPF takes one DNS entry.

FAQ

Frequently asked questions

Can I have more than one SPF record?
No — having two SPF records is a configuration error. Merge them into one record using multiple `include:` entries.

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