Headers Security
critical Severity
Free Check
HSTS Enabled (Strict-Transport-Security)
Tells browsers to only access your site over HTTPS, preventing protocol downgrade attacks.
Why It Matters
Protects users against SSL-stripping and man-in-the-middle network tampering on insecure networks like airport or cafe Wi-Fi.
How We Check This
We verify the Strict-Transport-Security header has a max-age of at least 31536000 seconds (1 year) and includes the includeSubDomains directive.
How to Fix & Implement
Copy-paste configuration blocks tailored for your web server or edge proxy.
nginx snippet
add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;
Frequently Asked Questions
What is HSTS preloading?
Preloading submits your domain to a hardcoded browser list baked into Chrome, Firefox, and Safari so even the first visit is HTTPS.