SPF record validator

Validate SPF syntax

Validate and analyse SPF TXT records directly in your browser. Quickly detect syntax problems, understand what each mechanism does, and spot risky patterns before you publish or troubleshoot your email setup.

This tool is useful for sysadmins, email admins, and domain owners working with SPF policies for Google Workspace, Microsoft 365, mail gateways, or custom mail servers.

How to use

  • Paste your SPF TXT record into the input field.
  • Click Validate record.
  • Review the summary, warnings, and actionable fixes.
  • Check each parsed mechanism or modifier for explanation and context.
  • Copy the normalised SPF record if needed.

FAQ

SPF validation help

An SPF record is a DNS TXT record that tells receiving mail servers which systems are allowed to send email for your domain. It helps reduce spoofing and improves email authentication.

If SPF is missing or misconfigured, legitimate mail can fail checks and fake mail can be harder to detect.

Practical examples

Example 1 — strict custom sender

v=spf1 ip4:203.0.113.10 -all

This record allows only one IPv4 address to send mail for the domain. Everything else fails SPF.

Example 2 — Google Workspace with softfail

v=spf1 include:_spf.google.com ~all

This is common during rollout. Google is authorised, while all other senders get softfail instead of hard fail.

Example 3 — record with a warning

v=spf1 -all include:_spf.google.com

This record is structurally wrong in practice because all appears too early. The validator should warn that all should normally be the final mechanism.

Example 4 — lookup-heavy SPF

v=spf1 include:_spf.google.com include:spf.protection.outlook.com a mx exists:%{i}.spf.example.com ~all

This record may be valid, but it increases DNS lookup pressure. The tool highlights this so you can simplify the policy before it becomes fragile.

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