DMARCReport is an email deliver troubleshooting tool every business must have.

The DMARC framework allows email admins to determine what happens with an outgoing email from a domain which does not comply with SPF restrictions and/or does not have a (valid) DKIM signature (i.e. there is a strong chance said message has been spoofed).

Such restrictions effectively obliterate the chance of sending forged/spoofed emails (most MTAs will drop them on sight, and for those who don't, inbound spam filters will do the rest).

The problem is that sometimes the DMARC policy can prevent delivery of legit emails: for example, when we add a new transactional email delivery service and forget to update our SPF/DKIM records.

To fix this, the DMARC specs allows reporting, and DMARCReport is a tool that makes the analysis of such reports very easy.

More often than not, an active online business will have multiple domains, or subdomains of a main domain, to handle different kinds of outgoing emails: interpersonal, transactional, marketing, etc. DMARCReports will help users track all these different (sub)domains from one simple dashboard, and quickly take care of any cases where legit emails are blocked from delivery.

In my opinion, the value provided by this LTD is insanely high.

One can track an unlimited number of domains, and the limit of 10,000 messages per month can go a really long way. Even if one sends more emails than that, those needn't be tracked at all times; the critical moment is the establishment of a new sending route, and for subsequent periods the number of reported messages can be reduced from 100% to a much lower number.

There are some inelegancies in the UI; the white label function leaves much more to be desired (the same logo is used both on dark and light background, which is guaranteed to make either look ugly); it doesn't work well on tablets.

But these are minuscule gripes. Even with those, this purchase is a no-brainer. It works as required, it has a lot of features (including support for MTA-STS, another emerging standard to improve email privacy), and it offers ample monthly limits. The subscription pricing (in case usage outgrows the LTD limits) is also very fair, in my opinion.

Caution: the Appsumo deal page says the deal is not stackable; the DMARCReport own site says one can stack up to 3 codes. So even if you need to regularly track more than 10K email/month, you might be lucky and fit into a larger LTD tier.