MailTest

About

Your emails meet SPF, DKIM, and DMARC requirements but still go to spam. While other tools simply report a DKIM failure, MailTest provides the reason why. It runs 11 technical checks to deliver clear, actionable insights, pinpointing the exact problem and its solution. This self-hosted tool is open source after 100 users and designed for developers seeking definitive answers beyond basic pass/fail indicators. You can try it for free with three daily tests and no credit card required.