MailTest

What it does

SPF ✅ DKIM ✅ DMARC ✅ — yet your emails still land in spam? Most tools just say "DKIM failed" without explaining WHY. MailTest goes deeper: 12 technical checks + actionable insights that show you exactly what's broken and how to fix it. Self-hosted, open source (after 100 users), built for developers who need real answers, not just red/green checkmarks. Try it free: 3 tests/day, no credit card.

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  MailTestedNov 2025 · ▲7

  Check why your emails go to spam — instantly.

• VT
  VaultSandbox – Test your real MailGun/SES/etc. integrationJan 2026 · vaultsandbox.com · ▲58

  I've spent the last few months working on something I wish I'd had years ago. I kept running into the same issue: CI green, production mail broken. TLS handshake failures, DKIM alignment mismatches, SPF soft-fails ... the stuff that only surfaces when real mail servers are involved. Most test tools (Mailpit, MailHog) are catch-alls. They confirm "an email was sent" but don't validate the protocol. They also aren't designed for network-exposed environments: no auth, unprotected Web UI, easy to enumerate messages. VaultSandbox is my attempt at fixing that. It's a self-hosted SMTP gateway…

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  Email InspectNov 2025 · ▲9

  Free dmarc, spf & dkim analyzer tools

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  Free SMTP Tester - Get Your Spam ScoreMay 2026 · nesdzo.co.uk · ▲3

  Test SMTP, SPF, DKIM, DMARC & spam score. No signup.

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  InboxGreenMay 2026 · inboxgreen.email · ▲1

  Free email deliverability checker for SPF, DKIM & DMARC

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  Email DNS CheckMar 2026

  Diagnose SPF, DKIM and DMARC errors instantly

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