HTTP header analysis for https://facebook.com

HTTP Headers Analyzer

4 / 10

https://facebook.com

WordPress → Browser
3 missing headers, 3 warnings, 8 notices

Value

Explanation

accept-encoding

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.

coop_report="https://www.facebook.com/browser_reporting/coop/?minimize=0", default="https://www.facebook.com/ajax/browser_error_reports/?device_level=unknown&brsid=7524090308151605366&cpp=c3&cv=1024476753&st=1751838789150", permissions_policy="https://www.facebook.com/ajax/browser_error_reports/"

{"max_age":2592000,"endpoints":[{"url":"https:\/\/www.facebook.com\/browser_reporting\/coop\/?minimize=0"}],"group":"coop_report","include_subdomains":true}, {"max_age":259200,"endpoints":[{"url":"https:\/\/www.facebook.com\/ajax\/browser_error_reports\/?device_level=unknown&brsid=7524090308151605366&cpp=c3&cv=1024476753&st=1751838789150"}]}, {"max_age":21600,"endpoints":[{"url":"https:\/\/www.facebook.com\/ajax\/browser_error_reports\/"}],"group":"permissions_policy"}

This header is part of the Reporting API specification. They are used to configure the reporting of network errors and other issues to a specified endpoint.
The Report-To header specifies where reports should be sent.
group defines the reporting group. Groups allow reports to be grouped logically; e.g. there could be a group for network errors and a second group for browser feature deprecation reports.
max_age defines the number of seconds the browser should remember these settings. Prevents the browser from having to parse the JSON on each request.
endpoints defines one or more URLs where the reports need to be send to. Multiple URLs can be specified for failover and load-balancing. Endpoints can be assigned a weight to distribute load, with each endpoint receiving a specified fraction of the reporting traffic. Endpoints can also be assigned a priority to set up fallback collectors.
include_subdomains is a boolean that enables or disables NEL reporting for subdomains of the origin.

default-src blob: 'self' https://*.fbsbx.com *.facebook.com *.fbcdn.net;script-src *.facebook.com *.fbcdn.net *.facebook.net 127.0.0.1:* 'nonce-ddsevr3r' blob: 'self' connect.facebook.net 'unsafe-eval' https://*.google-analytics.com *.google.com;style-src *.fbcdn.net data: *.facebook.com 'unsafe-inline' https://fonts.googleapis.com;connect-src *.facebook.com facebook.com *.fbcdn.net *.facebook.net wss://*.facebook.com:* wss://*.whatsapp.com:* wss://*.fbcdn.net attachment.fbsbx.com ws://localhost:* blob: *.cdninstagram.com 'self' http://localhost:3103 wss://gateway.facebook.com wss://edge-chat.facebook.com wss://snaptu-d.facebook.com wss://kaios-d.facebook.com/ v.whatsapp.net *.fbsbx.com *.fb.com https://*.google-analytics.com;font-src data: *.facebook.com *.fbcdn.net *.fbsbx.com https://fonts.gstatic.com;img-src *.fbcdn.net *.facebook.com data: https://*.fbsbx.com facebook.com *.cdninstagram.com fbsbx.com fbcdn.net connect.facebook.net *.carriersignal.info blob: android-webview-video-poster: *.whatsapp.net *.fb.com *.oculuscdn.com *.tenor.co *.tenor.com *.giphy.com https://trustly.one/ https://*.trustly.one/ https://paywithmybank.com/ https://*.paywithmybank.com/ https://www.googleadservices.com https://googleads.g.doubleclick.net https://*.google-analytics.com;media-src *.cdninstagram.com blob: *.fbcdn.net *.fbsbx.com www.facebook.com *.facebook.com data: *.tenor.co *.tenor.com https://*.giphy.com;child-src data: blob: 'self' https://*.fbsbx.com *.facebook.com *.fbcdn.net;frame-src *.facebook.com *.fbsbx.com fbsbx.com data: www.instagram.com *.fbcdn.net accounts.meta.com https://trustly.one/ https://*.trustly.one/ https://paywithmybank.com/ https://*.paywithmybank.com/ https://www.googleadservices.com https://googleads.g.doubleclick.net https://www.google.com https://td.doubleclick.net *.google.com *.doubleclick.net;manifest-src data: blob: 'self' https://*.fbsbx.com *.facebook.com *.fbcdn.net;object-src data: blob: 'self' https://*.fbsbx.com *.facebook.com *.fbcdn.net;worker-src blob: *.facebook.com data:;block-all-mixed-content;upgrade-insecure-requests;

The Content Security Policy (CSP) header helps prevent cross-site scripting (XSS), clickjacking, and other code injection attacks by specifying which dynamic resources are allowed to load.
default-src sets the default policy for fetching resources like JavaScript, images, CSS, fonts, AJAX requests, frames, HTML5 media.
script-src specifies valid sources for JavaScript. This includes not only URLs loaded directly into <script> elements, but also things like inline script event handlers (onclick) and XSLT stylesheets which can trigger script execution.
object-src defines what <object>, <embed> and <applet> elements are allowed to be loaded and executed.
style-src defines what CSS stylesheets are allowed to be loaded.
media-src defines what <audio>, <video> and <track> elements are allowed to be loaded.
img-src defines what images and favicons can be loaded.
worker-src defines what workers scripts (e.g. Worker, ServiceWorker or SharedWorker) can be loaded and executed.
font-src defines what fonts can be loaded using CSS's font-face.
frame-src defines what <frame> and <iframe> elements can be loaded.
child-src defines what <frame>, <iframe> or workers can be loaded.
manifest-src defines what manifest files can be loaded.
upgrade-insecure-requests instructs browsers to replace insecure URLs (HTTP) with secure URLs (HTTPS).

force-load-at-top

include-js-call-stacks-in-crash-reports

accelerometer=(), attribution-reporting=(self), autoplay=(), bluetooth=(), browsing-topics=(self), camera=(self), ch-device-memory=(), ch-downlink=(), ch-dpr=(), ch-ect=(), ch-rtt=(), ch-save-data=(), ch-ua-arch=(), ch-ua-bitness=(), ch-viewport-height=(), ch-viewport-width=(), ch-width=(), clipboard-read=(self), clipboard-write=(self), compute-pressure=(), display-capture=(self), encrypted-media=(self), fullscreen=(self), gamepad=*, geolocation=(self), gyroscope=(), hid=(), idle-detection=(), interest-cohort=(self), keyboard-map=(), local-fonts=(), magnetometer=(), microphone=(self), midi=(), otp-credentials=(), payment=(), picture-in-picture=(self), private-state-token-issuance=(), publickey-credentials-get=(self), screen-wake-lock=(), serial=(), shared-storage=(), shared-storage-select-url=(), private-state-token-redemption=(), usb=(), unload=(self), window-management=(), xr-spatial-tracking=(self);report-to="permissions_policy"

Instructs a browser to selectively allow or deny certain browser APIs and features. It helps improve security.

same-origin

The Cross-Origin-Resource-Policy header is part of the Fetch metadata request headers. It controls how resources can be shared across origins, enhancing security by preventing unauthorized access to resources.
same-origin means the resource can only be loaded by documents from the same origin.

same-origin-allow-popups

A Cross-Origin Opener Policy (COOP) header specifies how this page's browsing context can be shared when opened in a 'browser tab', 'popup', 'iframe', etc. The policy can force the creation of a new top-level browsing context to make sure the browser context is protected or isolated.
same-origin-allow-popups specifies that if a popup is created, and the popup comes from the same origin, then we have full access to that popup.

no-cache

Warning The page can't be cached by any shared caches such as Varnish or a CDN. If the page is something everybody can access, this behavior is not desired.
Notice Pragma is a HTTP/1.0 header. This request uses HTTP/1.1. In HTTP/1.1, Pragma is deprecated and superseded by the Cache-Control header. Remove Pragma to save bandwidth and processing power.

private, no-cache, no-store, must-revalidate

private means the response can only be stored by the browser's cache, but not by CDNs, proxies, or any other shared caches.
no-cache means the response can be stored by any cache, but the stored response must be validated with the origin server before each reuse. If the origin confirms that the response hasn't changed, downloading of the full response body can be skipped.
Warning no-cache will cause a revalidation request to the origin server for every use of the cached response. Consider using public with appropriate max-age to improve caching efficiency.
Warning no-store means the response may not be stored in any cache, including the browser's cache.
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.
Notice It does not make sense to set must-revalidate with no-store; when nothing is cached, there is nothing to revalidate.
Notice It does not make sense to set must-revalidate with no-cache; must-revalidate is implied.
Notice no-store is set, so it does not make sense to set no-cache as well.
Notice no-store is set, so it does not make sense to set private as well.

sat, 01 jan 2000 00:00:00 gmt

This Expires date is in the past: the page is considered stale and will be removed from all caches.
Notice Because there is a Cache-Control header with a max-age and/or s-maxage directive, the Expires header will be ignored. Consider removing Expires to save bandwidth and processing power.

nosniff

The X-Content-Type-Options header, when set to nosniff, prevents MIME type sniffing. This enhances security by ensuring browsers respect the declared Content-Type of the response, mitigating MIME confusion attacks.
The value nosniff is correctly set, providing protection against MIME type sniffing attacks.

This header enables the browser's built-in XSS protection. However, it's considered legacy and modern browsers may ignore it.

deny

X-Frame-Options prevents this URL from being embedded in an iframe. This protects against clickjacking attacks.
deny means that this page can never be displayed in an iframe. It's the most secure option.

A security header that enables or disables the "Origin-Agent-Cluster" isolation for a document. When set to "?1", it indicates that the document should be placed in an origin-keyed agent cluster, which can enhance security isolation.

max-age=15552000; preload

The Strict-Transport-Security header (HSTS) instructs browsers to only use HTTPS for future connections to this domain, enhancing security by preventing downgrade attacks and cookie hijacking.
max-age specifies the time, in seconds, that the browser should remember to use HTTPS only for this domain.
Notice For optimal security, consider increasing max-age to at least 31,536,000 seconds (1 year), especially if you're considering preloading.
preload recommends the domain for inclusion in browsers' preload lists. If accepted, the domain would get hardcoded into browsers as HTTPS-only.
Notice In order to be eligible for preloading, max-age must be least 31,536,000 seconds (roughly 1 year).

text/html; charset="utf-8"

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

u1j77lt0hemkxz7qqfq05bxq7aqvirldalgqnvstp1zo6pojpvarj9cmoq34ehsc06bfuqikypo6ogincv330g==

sun, 06 jul 2025 21:53:09 gmt

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.

excellent; q=0.9, rtt=10, rtx=0, c=10, mss=1380, tbw=3909, tp=-1, tpl=-1, uplat=60, ullat=0

h3=":443"; ma=86400

The alt-svc header advertises alternative services for accessing the same resource, enabling protocol negotiation and potential performance improvements.
h3 indicates that HTTP/3 is supported. Variants like h3-29 refer to specific drafts of the HTTP/3 protocol.
ma=86400 specifies that the alternative service information is fresh for 86400 seconds.

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 Cross-Origin-Embedder-Policy to specify how this page can be loaded by cross-origin resources.

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

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