// domain tool
Free Security Headers tool.
Free Security Headers lookup — audits hsts, csp, x-content-type-options, x-frame-options, referrer-policy, and permissions-policy.
// more tools
Other DNS & domain tools
MX Lookup
Mail servers & email delivery
NS Lookup
DNS hosting & delegation
A Record Lookup
IPv4 addresses
AAAA Records
IPv6 addresses
CNAME Records
Canonical aliases
CAA Records
Certificate authority restrictions
SOA Record
Start of Authority
TXT Record Lookup
SPF, verification & more
SPF Record Checker
Email sender authorization
DMARC Checker
Email authentication policy
DKIM Selectors
22-selector probe
WHOIS Lookup
Registration & ownership info
IP Lookup
IPv4 & IPv6 addresses
ASN / Origin
AS number, name, country
IP Geolocation
Country, region, ISP
RDAP Lookup
Full registration data via RDAP
Propagation Check
Compare DNS across providers
Reverse DNS
PTR record lookup
Subdomain Discovery
CT log subdomain scanner
HTTP Headers
Response headers, server-side
TLS Certificate
Cert details from CT logs
Server Information
Headers, redirects, tech stack
Security Analysis
Overall grade + audit
DNS Lookup
Complete DNS record lookup
Email Security Checker
Full email security analysis