Free IT Toolbox
Website security and SSL checker.
Check a public website's certificate issuer and expiry, hostname match, TLS version, HTTPS redirect chain and browser security headers. This tool sends the domain to our server and public DNS resolvers, then connects to that website over HTTPS. No account is needed.
Reading the result
What this checker looks at.
It starts at the HTTPS address for the exact domain you enter. Type the www name as well when visitors use it, because it can have a different certificate or redirect.
Certificate and expiry
See who issued the certificate, when it expires and whether the name on it matches the website address.
TLS version
See whether the connection negotiated TLS 1.2 or TLS 1.3. TLS is the encryption standard defined for version 1.3 in RFC 8446.
HTTPS redirect chain
Follow up to five public HTTPS redirects from the domain root. HTTP downgrades, IP addresses and custom ports are refused.
Security headers
Read HSTS, Content Security Policy, framing, MIME, referrer and permissions headers on the final page, each explained in one line.
This is one public HTTPS homepage check at one moment. It does not scan other pages, forms, ports or software for vulnerabilities, and it is not a penetration test. Different servers behind the same domain can return different certificates or headers.
If a certificate is invalid, the checker reports what the server presented and stops before trusting the page or its headers. It does not follow a redirect to plain HTTP, an IP address, a private address, a URL with credentials or a port other than 443.
HSTS is defined in RFC 6797. HTTP status codes and header fields are covered by RFC 9110. Results may be cached for one minute.
For email security, domain protection and speed as well, run the Free Technology Checkup.
See everything in the Free IT Toolbox
Related tools: Email Security Checker, SPF Lookup Analyzer, DMARC Record Generator, SPF Record Generator, Email Header Analyzer, DNS Lookup, Microsoft 365 DNS Checker.
Let’s take a look at your setup.
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Prefer email? support@getwittco.com