---
title: "SPF records explained"
description: "What Sender Policy Framework does, how SPF TXT records work, and common mistakes."
translationKey: "email-spf-explained"
tags: [spf, dns, txt]
publishedAt: "2026-05-01"
lastReviewedAt: "2026-05-01"
indexable: true
faq:
  - question: "Why should only one SPF TXT exist per sending hostname?"
    answer: "Multiple SPF TXT records at the same name make SPF invalid for many receivers, so authorized mail can fail policy checks unexpectedly."
  - question: "Does SPF validate the visible From header?"
    answer: "SPF checks the envelope sender (typically Return-Path), while DMARC ties results to the header From domain when alignment is required."
---
> **Canonical:** https://formreceipt.com/docs/email-deliverability/spf-explained

## What SPF does

SPF lets receiving mail servers check whether an outbound server is authorized to send mail for your domain. The domain publishes a DNS TXT record listing permitted senders.

## Syntax basics

SPF TXT records start with `v=spf1`, list mechanisms (`include`, `a`, `mx`, `ip4`), and end with an all mechanism such as `-all` or `~all`.

## One TXT per SPF

You should publish **only one** SPF TXT record for a given domain or label. Multiple SPF TXT records invalidate SPF for many receivers.

## Related reading

After SPF is stable, align reporting with [DMARC explained](/docs/email-deliverability/dmarc-explained).