Checks for the presence of the Strict-Transport-Security header.
HSTS (HTTP Strict Transport Security) is a security header that tells browsers they should only ever communicate with your site using HTTPS, never HTTP.
It protects against protocol downgrade attacks and cookie hijacking. Once a browser sees the HSTS header, it will automatically convert all future HTTP requests to HTTPS, even if a user types `http://` or clicks an HTTP link.
It's an important security enhancement that hardens your site's HTTPS implementation.
# Example HSTS Header
Strict-Transport-Security: max-age=31536000; includeSubDomains; preloadRun a free audit to see how your site performs on HSTS Test and 159 other checks.
Start Free AuditVerifies the validity and configuration of the SSL certificate.
Checks if the site is secured with a valid SSL certificate.
Ensures that HTTP traffic is automatically redirected to HTTPS.
Checks for insecure (HTTP) resources on a secure (HTTPS) page.