P Postulate

Free SPF Record Checker

Look up and validate any domain's SPF record. See parsed mechanisms, count DNS lookups against the RFC 7208 limit, and get actionable fixes.

What is SPF?

Sender Policy Framework (SPF) is a DNS-based email authentication method that lets domain owners specify which mail servers are authorized to send email on their behalf. Receiving servers check the SPF record to verify the sender, helping prevent spoofing and improve deliverability.

An SPF record is a TXT record on your domain that starts with v=spf1 followed by a series of mechanisms and modifiers that define your sending policy.

Quick Reference

Mechanism Description
ip4 / ip6 Authorize a specific IPv4 or IPv6 address or range
include Include another domain's SPF record (costs 1 DNS lookup)
a Authorize the domain's A/AAAA records (costs 1 DNS lookup)
mx Authorize the domain's MX servers (costs 1 DNS lookup)
redirect= Replace this policy with another domain's SPF record
all Match all senders — qualifier determines the action (pass/fail/softfail/neutral)

Need EU-hosted email infrastructure?

Postulate is a developer-first email API hosted entirely in the EU. Join the waitlist.