We started SimpleDMARC 5 years ago to make DMARC implementation less painful for IT teams and MSPs managing multiple domains. What began as a monitoring tool has grown into a full email authentication platform — and today we shipped a complete rebuild. The new version includes 30+ free tools covering the full email authentication stack: — DMARC: record checker, generator, policy validator, alignment analyzer — SPF: record checker, generator, flattener (for the 10-lookup limit problem) — DKIM: key validator, selector checker, rotation helper — BIMI: record validator, VMC checker, logo preview — MTA-STS: policy generator, validator, TLS-RPT checker — Diagnostics: email header analyzer, phishing URL checker, blacklist checker Everything is free, instant, no account required. We built these because we kept needing them ourselves and nothing free was specific enough about what was actually wrong. The thing that frustrates us most about existing DMARC tools: they tell you something is failing but not which sending source, not why the alignment is broken, and not what an attacker can actually do with your current policy. Ours tries to answer all three. Technical stack if anyone's curious: Vue 3, Fastify, PostgreSQL, BullMQ for report processing, AWS Route 53 for DNS automation. Happy to go deep on DMARC implementation, SPF flattening edge cases, DKIM rotation without breaking mail flow, or anything else email authentication. Five years of edge cases means we've probably seen your problem before.

This is such a wonderful tool as dmarc is something which is not that much known to the people. It is one of the best ways to protect your email. I think this tool is offering 30 free email authentication tools. I strongly recommend and will keep using the same. Thank you very much.