The type of the message body, specified as a MIME type.

The date and time at which the request was made. A browser uses it for age calculations rather than using its own internal date and time; e.g. when comparing against Max-Age or Expires.

The X-Content-Type-Options header prevents browsers from guessing a response's content type. Without it, browsers may interpret files differently than intended, which can lead to security vulnerabilities.
The value nosniff is correctly set.

Specifies how the resource is compressed. Not to be confused with Transfer-Encoding which specifies how the data is transferred.
gzip means that the data is compressed with gzip.
Warning Add a Content-Length header. The Content-Length header is required, unless the message is transported using chunked encoding. Without a Content-Length header some servers will respond with 400 (bad request) or terminate connections early.

Identifies the software used by the origin server to handle the request (e.g. Apache, Nginx, Cloudflare).
Notice Consider removing or minimizing the Server header. Even without a version number, it reveals the server software, which aids reconnaissance.

public means the response may be stored by all caches, including browser caches, CDNs, and shared caches.
max-age specifies the maximum amount of seconds a page is considered valid. The higher max-age, the longer a page can be cached.
Notice A max-age of 5 seconds is short, especially if your content doesn't change frequently. Consider increasing max-age unless the URL has live updates.
must-revalidate indicates that once a page becomes stale, both shared caches and browser caches must not use their stale copy without validating it with the origin server first.

A legacy header that enables the browser's built-in cross-site scripting (XSS) filter. Modern browsers ignore it in favor of Content-Security-Policy.
1 enables XSS filtering.
mode=block blocks the response entirely if an attack is detected, instead of sanitizing the page.
Notice Add a Content-Security-Policy header for more comprehensive protection.

The Vary header specifies a list of headers that must be considered when caching responses. For a cached response to be used, these headers must match between the cached response and the new request. This ensures that the appropriate version of a resource is served based on factors like language, encoding, or device type.

The Via header tracks how a page is forwarded from proxy to proxy. Beware, not all proxies append themselves to the Via header.

The page was not served from Amazon CloudFront.

Amazon CloudFront's edge servers that were queried for the request. The first 3 letters are an IATA location code.

A unique request identifier generated by Amazon CloudFront. This ID can be used to troubleshoot the request and trace it through Amazon's network.

missing Add a Strict-Transport-Security header. The Strict-Transport-Security header or HSTS header is used to instruct browsers to only use HTTPS, instead of using HTTP. It helps enforce secure communication.

missing Add a Content-Security-Policy header. The Content-Security-Policy header helps browsers prevent cross site scripting (XSS) and data injection attacks.

missing Add a Referrer-Policy header. When a visitor navigates from one page to another, browsers often pass along referrer information. The Referrer-Policy header controls how much referrer information a browser can share. This is important to configure when private information is embedded in the path or query string and passed onto an external destination.

missing Add a Permissions-Policy header. Restrict access to device features like the camera, microphone, location, accelerometer and much more.

missing Add a Cross-Origin-Embedder-Policy header. It requires cross-origin resources to explicitly consent before this page can load them, protecting those resources from being exposed to Spectre-style timing attacks. Together with Cross-Origin-Opener-Policy, it enables cross-origin isolation and access to SharedArrayBuffer.

missing Add a Cross-Origin-Opener-Policy header. It prevents other sites from retaining a window reference to this page when opened via window.open() or navigation, blocking script-based attacks through shared browsing contexts.

missing Add a Cross-Origin-Resource-Policy header. It controls which origins can embed or load this page's resources (images, scripts, etc.), preventing hotlinking and cross-origin data leaks.

missing Add a X-Frame-Options header. The X-Frame-Options header prevents this URL from being embedded in an iframe. This protects against clickjacking attacks. Alternatively, set a Content-Security-Policy header with a frame-ancestors directive.

missing Add a X-Permitted-Cross-Domain-Policies header to prevent Flash, Adobe Reader and other clients from sharing data across domains.