Free DMARC Weekly Digests by Postmark vs.
Mail Tower in 2026

Postmark's free weekly digest gave us a compact view of our highest-volume senders. Microsoft 365 and Google Workspace appeared clearly enough for the corporate domain, and the SPF pass with domain match and DKIM pass with domain match cases were easy to accept as expected traffic. The tradeoff was depth: SendGrid and Mailchimp on the marketing subdomain competed for limited top-source space, the DKIM pass on a subdomain needed manual interpretation, and the unknown sender had to be classified outside the digest.

Mail Tower had more working surface area for the same test. We could compare Microsoft 365, Google Workspace, SendGrid, Mailchimp, and the support desk sender across the three domains, then filter into pass, fail, and DMARC match patterns. The forwarded mail with SPF failure was easier to separate from the unauthorized spoof sample, although we still wanted clearer fix guidance when a sender was legitimate but used a nonmatching domain.

Postmark onboarding was the shortest path in the test. We added the corporate domain first, then the parked domain, and DNS verification was clear enough for a non-specialist to complete with a simple TXT record handoff. The weak spot appeared once the marketing subdomain started producing mixed SendGrid and Mailchimp traffic: the weekly digest told us what changed, but it did not give a comfortable investigation flow for the unknown sender.

Mail Tower required more decisions during onboarding because our primary domain, marketing subdomain, and parked domain each had their own context. Once configured, it felt more usable for daily DMARC work. We could find the unknown sender by filtering low-volume sources, explain that the forwarded mail failed SPF because the forwarder broke SPF authentication, and keep the unauthorized spoof sample separate from legitimate senders that only needed domain-match cleanup.

Postmark gave us enough setup direction to create the reporting record and start receiving weekly results. When we treated the marketing subdomain as a separate operating area, the support expectation stayed light: we could verify DNS, but we had to write our own handoff notes for SendGrid, Mailchimp, and the support desk sender. That was acceptable for a free monitor, but not enough for a team trying to justify quarantine or reject.

Mail Tower's paid tiers created a stronger expectation of operational support. The DNS handoff was workable for all three domains, and account setup gave us a clearer place to explain which team owned Microsoft 365, Google Workspace, marketing automation, and the support desk. For enterprise onboarding, we would want a more explicit escalation route, because the unauthorized spoof sample and policy movement questions needed faster, traceable decisions.

Postmark made the most sense for the parked domain and for a primary corporate domain with stable Microsoft 365 and Google Workspace traffic. It did not feel natural for MSP handoff: there was no practical client grouping, recurring client reporting was limited to the weekly email shape, and we had to maintain separate notes for the marketing subdomain's SendGrid and Mailchimp changes.

Mail Tower fit the operator role better. We could group the corporate domain, marketing subdomain, and parked domain in a way that supported recurring review, and the public tiers made small and medium business sizing easier to explain. MSP use was only partial in our test: account separation and handoff notes were workable, but client-level alert routing and repeatable remediation workflows needed more maturity.