Every check evaluates public configuration, infrastructure telemetry, or security headers.
Check any website's TLS certificates, HTTP security headers, cookie flags, DNSSEC, open ports and threat-list status.
Whether privacy, malware and parental-control resolvers block the site
Which certificate authorities may issue certificates for the domain
Cookies set on arrival, and how tightly each one is scoped
Known data breaches of the site, as recorded by Have I Been Pwned
DNSSEC records proving DNS answers have not been tampered with
Which web application firewall, if any, sits in front of the site
Every HTTP response header the server sends back
Whether browsers are told to only ever connect over HTTPS
Protective headers such as CSP, X-Frame-Options and nosniff
Abuse confidence score, blacklist status, and incident reports via AbuseIPDB
Whether the site appears on common malware and phishing lists
Insecure resources on the page, and third-party scripts without SRI
Which common ports are open and reachable on the host
The security.txt file, and who it says to contact about vulnerabilities
Social accounts the site claims, and whether they link back
Certificate issuer, validity dates and the chain of trust
Whether Chrome, Safari, Java and older Android can still connect
The TLS versions accepted, and the cipher and details of a live handshake
SSL Labs' grade for the server's TLS configuration
Analytics, ad trackers and other third parties the page loads
CVEs Shodan links to the services running on the host
Check any website's crawl rules, sitemap, canonical and social tags, redirect chains, global ranking and archived history.
How the site has changed over time, via the Wayback Machine
Estimated CO2 from the data needed to load the page
The crawl rules the site publishes for search engines and AI crawlers
Tranco rank, if the site is in the global top million
Internal and external links found in the page's anchor tags
Lighthouse scores for performance, accessibility, SEO and best practice
The full chain of redirects before the final page loads
A full-page render of the site, as a browser sees it
The pages a site lists in its own sitemap
Open Graph and Twitter tags used when the site is shared
Check where any website is hosted, what software it runs, which ports are open, and the network route packets take to reach it.
Other hostnames Shodan has seen on the same IP address
Operating system, ASN and the network the host sits on
Where in the world the server is physically hosted
Whether the site is up, and how quickly it responded
Frameworks, analytics and services the site is built with
The network path packets travel to reach the server
Look up WHOIS registration, DNS and TXT records, nameservers, DNSSEC and subdomains for any domain name.
A, AAAA, MX, NS, CNAME and other records held for the domain
Which nameservers answer for the domain, and their IP addresses
Ownership and contact details published against the domain
Subdomains that have appeared in public Certificate Transparency logs
TXT records, including domain verification and policy entries
Registrar, registration dates and nameservers, from WHOIS
Check a domain's MX routing, SPF, DKIM and DMARC policies, TXT records, and whether filtering resolvers block it.
MX, SPF, DKIM and DMARC records for sending and receiving mail
Measure any page with Lighthouse, and check its redirect chain, server response time and estimated carbon footprint.
Check the cookies a website sets on arrival, the third-party technology it loads, its WHOIS exposure and its threat-list status.