SPF ✅ DKIM ✅ DMARC ✅ — yet your emails still land in spam? Most tools just say "DKIM failed" without explaining WHY. MailTest goes deeper: 11 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.