Free SPF Record Checker

Validate your SPF record, check the 10-lookup limit, and generate optimized SPF records with our free tool.

SPF Record Validator

Check your SPF record for syntax errors, DNS lookup limits, and best practices

SPF Record Generator

Build custom SPF records with an interactive mechanism builder and automatic flattening

Quick Templates:

SPF Flattening Tool

Reduce DNS lookups by converting SPF includes to IP addresses. Helps you stay under the 10-lookup limit.

What is SPF (Sender Policy Framework)?

Overview

SPF (Sender Policy Framework) is an email authentication method that helps prevent email spoofing by allowing domain owners to specify which mail servers are authorized to send email on behalf of their domain. When configured correctly, SPF helps improve email deliverability and protects your domain from being used in phishing attacks.

The 10-Lookup Limit

RFC 7208 specifies that SPF validation must not perform more than 10 DNS lookups. This includes lookups for include, a, mx, ptr, and exists mechanisms. If your SPF record exceeds this limit, some email receivers may fail your SPF validation, causing deliverability issues.

Common Issues

  • Multiple SPF records (only one is allowed per domain)
  • Exceeding the 10 DNS lookup limit
  • Syntax errors in SPF mechanisms
  • Missing or incorrect qualifiers (~all vs -all)
  • Not updating SPF when changing email providers

Best Practices

  • Keep your SPF record under 10 DNS lookups
  • Use SPF flattening for complex configurations
  • Start with ~all (soft fail) and move to -all (hard fail) after testing
  • Regularly audit your SPF record when adding new email services
  • Test changes before applying them to production