DeliverGuard — self-hosted email deliverability doctor

Helps self-hosted email users find out why mail lands in spam or gets the IP banned

Problem

Developers follow tutorials, set up SPF, DKIM, DMARC and reverse DNS on a VPS, send a few test emails to Outlook/Hotmail and they all land in spam; a day later the IP is banned and the provider refuses to explain why. What people need is not another setup guide but an actionable diagnosis of their own domain and IP.

Solution

Users enter their domain and sending IP; the product checks SPF/DKIM/DMARC, rDNS, blacklists and DNS consistency, and returns item-by-item fixes. A test inbox network sends probes to major providers and aggregates where they land, and blocked users get an appeal-template generator plus an IP warm-up plan.

Users

Self-hosting enthusiasts, small-team ops, indie developers, mailing-list operators

MVP

One-click domain and IP health report; delivery probes to major inboxes with result aggregation; prioritized fix list; appeal template and warm-up plan for blocked IPs; exportable PDF report

Revenue

Per-check fees or a $9–19/mo subscription; free tier gives the health report and suggestions, paid tier adds the test inbox network and continuous monitoring

Why now

More developers are trying self-hosted email while anti-spam policies get stricter and more opaque; diagnosing this black-box problem is a visible community pain, and the stack is just DNS plus an SMTP client — very doable solo.