Independent consultant here — built some free SPF/DKIM/DMARC diagnostic tools. Roast them?
Hey all — I'm an independent consultant doing Google Workspace + email deliverability work (since 2018). I got tired of bouncing between half a dozen lookup sites when triaging a client's auth, so I built a few free tools. No signup, no paywall.
Before I lean on these more with clients, I'd really value a tear-down from people who do this every day — you'll catch the false positives and missing checks I can't.
1. Deliverability check — paste a domain, get SPF/DKIM/DMARC/MX in plain English.
https://guanacostech.com/email-troubleshooter
• SPF: parses the record, counts DNS lookups, flags ~all/?all soft-fails and multiple SPF records.
• DKIM: probes ~40 common selectors — so a "not found" means "not on a common selector," not "no DKIM."
• DMARC: policy, alignment mode, pct. Also reports MTA-STS / TLS-RPT / BIMI presence.
• Does NOT check blocklists yet (roadmap). The score is opinionated.
2. Header analyzer — paste raw headers, get a verdict.
https://guanacostech.com/header-analyzer
• Traces hops, reads the receiver's Authentication-Results, computes SPF + DKIM alignment vs the From org-domain (multi-level TLDs), detects the ESP, and only flags spoofing when the mail is actually unauthenticated — so it doesn't scream "HIGH RISK" at legit ESP mail.
3. DMARC aggregate (RUA) report viewer — upload or paste the XML.
https://guanacostech.com/dmarc-analyzer
• Decompresses (.gz/.zip) and parses the report entirely in your browser — nothing is uploaded to a server. Groups by sending IP, shows pass rate + alignment, and calls out the legit senders that'll break at p=reject.
What I'm actually asking:
• Where do these give wrong or misleading verdicts? Especially false positives.
• What checks are you surprised aren't there?
• Is the deliverability score weighting sane, or would you weight it differently?
• Anything that'd embarrass me in front of people who actually know this stuff?
Full disclosure: the site (guanacostech.com) is my consultancy, so yes this is "my brand" — but the tools are genuinely free, nothing is gated, and I'm here for the technical feedback, not to pitch anyone. Happy to return the favor on anything you're building.
Thanks in advance for the honesty.