Headers Security
critical Severity
Free Check

HSTS Enabled (Strict-Transport-Security)

Tells browsers to only access your site over HTTPS, preventing protocol downgrade attacks.

Test Your Website for HSTS Enabled (Strict-Transport-Security)

Run this check along with 90+ automated tests across your domain.

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.