Host·Mortem
complete host diagnostics
DNS, SSL, headers, CORS, IP geolocation, email deliverability, WHOIS, and performance — nine panels, one target.
Most diagnostic tools cover one angle. HostMortem runs all ten checks against a single target — free, no account, no limits.
| Feature | HostMortem | MXToolbox | IntoDNS | Qualys SSL Labs | SecurityHeaders.com |
|---|---|---|---|---|---|
| DNS records (A, AAAA, MX, TXT, NS…) | |||||
| SSL/TLS certificate details | |||||
| HTTP security headers grading | |||||
| CORS policy check | |||||
| IP geolocation & ASN lookup | paid | ||||
| robots.txt & crawl rules | |||||
| Email deliverability (SPF, DKIM, DMARC) | |||||
| WHOIS & domain registration | partial | ||||
| Performance metrics | |||||
| All checks — one target, one run | |||||
| Free, no account required | partial |
Based on publicly documented features as of June 2026. Features may vary. Flatline indicates the feature was not found in standard free use of that tool.
A hostmortem is a complete diagnostic pass over a domain or IP address — the kind of investigation you'd normally piece together by hand from half a dozen separate tools. Instead of running a DNS lookup here, an SSL checker there, and a separate SPF/DMARC validator somewhere else, HostMortem fires all ten checks in parallel against a single target and lays the results out side by side. Most runs finish in under two seconds because nothing is queued sequentially — DNS, SSL, headers, CORS, IP, robots.txt, email authentication, WHOIS, performance, and the rolled-up security score all resolve at once.
It's built for the moments where a quick, complete read matters: after pointing a domain at a new host and needing to confirm every DNS record actually propagated; after issuing a fresh TLS certificate and wanting to verify HSTS and preload status without waiting for a slow scanner; while debugging why outbound email keeps landing in spam and needing SPF, DKIM, and DMARC checked together instead of one record at a time; or auditing an unfamiliar domain's security posture before doing business with it.
Every panel is documented twice — once in plain language for anyone who just wants to know what a result means, and once with the exact endpoint, query, and scoring formula behind it for engineers who want to reproduce or automate the check themselves. See the full documentation for the panel-by-panel breakdown, or read more about why HostMortem exists.
Common questions about what HostMortem checks and how to read the results.
HostMortem runs ten diagnostic checks against a single target: DNS records, SSL/TLS certificate details, HTTP security headers, CORS policy, IP geolocation and ASN, robots.txt crawl rules, email deliverability (SPF, DKIM, DMARC), WHOIS registration data, performance metrics, and a security headers scan — all in one run.
Yes, completely free — no account, no sign-up, no rate limits. Enter any domain or IP address and run the full diagnostic instantly.
HostMortem sends your target to a Cloudflare Worker API, which performs live lookups across all ten diagnostic panels simultaneously. Results stream back to your browser as each check completes. No data is stored.
These are email authentication protocols. SPF specifies which servers are authorized to send mail for your domain. DKIM adds a cryptographic signature to outgoing messages. DMARC tells receiving servers what to do when SPF or DKIM fails. All three are checked in the Email panel. See the Email docs for details.
Security headers like Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security protect against clickjacking, XSS, and protocol downgrade attacks. Many servers don't configure them by default. The Headers panel shows exactly which are missing. The Headers docs explain what each one does and how to set it.
Yes. Enter any IPv4 or IPv6 address in the search field. Most panels adapt automatically — the IP panel shows the address's owner, geolocation, and ASN regardless of whether you enter a domain or a raw IP.
After any change to DNS records, server configuration, or SSL certificate. Also useful when setting up a new domain, debugging email delivery failures, or preparing for a security audit.
WHOIS is a public database of domain registration records showing when a domain was registered, when it expires, and — unless privacy protection is enabled — the registrant's contact details. HostMortem's WHOIS panel pulls this data live.