Email authentication, made practical
DMARCGuardian
Clear guides for DMARC, SPF, DKIM, and BIMI, without the email-auth jargon.
DMARCGuardian helps email admins, founders, and operators understand why messages fail authentication, how to fix SPF and DKIM problems, and how to turn DMARC from a confusing DNS task into a clear process.
Core guides
Start with the fixes most teams need first
Start with the core guides if you are setting up DMARC for the first time, then use the blog for real-world failure cases, edge cases, and deliverability lessons. The goal of this site is simple: make email authentication understandable enough to implement correctly and maintain with confidence.
From the blog