HTTP Security Headers

Forces browsers to use HTTPS, preventing protocol-downgrade attacks.

Limits where scripts/resources can load from — the strongest defense against XSS.

Blocks the site from being embedded in iframes (clickjacking protection).

Stops browsers from MIME-sniffing responses away from the declared type.

Controls how much referrer information is sent to other sites.

Restricts access to browser features like camera, microphone, geolocation.