HTTP Headers Analyzer

6 / 10

https://bestseoskills.hashnode.dev/8171-bisp

Website → Cloudflare → Browser
2 missing headers, 2 warnings, 3 notices
JSON API

Header	Value	Explanation
date	wed, 15 jul 2026 01:28:03 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`.
content-type	text/html; charset=utf-8	The type of the message body, specified as a MIME type.
accept-ch	sec-ch-ua-bitness, sec-ch-ua-arch, sec-ch-ua-full-version, sec-ch-ua-mobile, sec-ch-ua-model, sec-ch-ua-platform-version, sec-ch-ua-full-version-list, sec-ch-ua-platform, sec-ch-ua, ua-bitness, ua-arch, ua-full-version, ua-mobile, ua-model, ua-platform-version, ua-platform, ua	The `Accept-CH` header asks the browser to include extra device and browser metadata on future requests. Client Hints are the structured, opt-in successor to the `User-Agent` string. Instead of one large string, the server explicitly requests the individual pieces it needs (CPU architecture, platform, browser version, etc.). The browser sends these as separate `Sec-CH-*` headers on subsequent requests. `sec-ch-ua-bitness`: Requests the bit architecture of the client's operating system, such as 32-bit or 64-bit. `sec-ch-ua-arch`: Requests the client's device CPU architecture, such as ARM or x86. `sec-ch-ua-full-version`: Requests the complete version number of the client's browser. `sec-ch-ua-mobile`: Requests a boolean hint indicating if the client's device is mobile. `sec-ch-ua-model`: Requests the model of the client's device. `sec-ch-ua-platform-version`: Requests the version of the operating system the client is running. `sec-ch-ua-full-version-list`: Requests a detailed list of version numbers for the client's browser and its significant components. `sec-ch-ua-platform`: Requests the operating system platform of the client's device, such as Windows or MacOS. `sec-ch-ua`: Requests a condensed version of the user agent string. `ua-bitness`: Requests the bit architecture of the client's operating system, such as 32-bit or 64-bit. `ua-arch`: Requests the client's device CPU architecture, such as ARM or x86. `ua-full-version`: Requests the complete version number of the client's browser. `ua-mobile`: Requests a boolean hint indicating if the client's device is mobile. `ua-model`: Requests the model of the client's device. `ua-platform-version`: Requests the version of the operating system the client is running. `ua-platform`: Requests the operating system platform of the client's device, such as Windows or MacOS. `ua`: Requests a condensed version of the user agent string.
cf-mitigated	challenge	Indicates that Cloudflare intercepted this request and took action before it reached the origin server. The value tells you what kind of action was taken: `challenge` means a CAPTCHA or JavaScript challenge was served, `block` means the request was blocked entirely. When this header is present, the response is from Cloudflare, not from the origin server.
content-security-policy	default-src 'none'; script-src 'nonce-ieey3zo9vkbwhk80je4wkz' 'unsafe-eval' https://challenges.cloudflare.com; script-src-attr 'none'; style-src 'unsafe-inline'; img-src 'self' https://challenges.cloudflare.com; connect-src 'self' https://challenges.cloudflare.com; frame-src 'self' https://challenges.cloudflare.com blob:; child-src 'self' https://challenges.cloudflare.com blob:; worker-src blob:; form-action http: https:; base-uri 'self'	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. `base-uri` defines what URLs can be used in the `<base>` element. `style-src` defines what CSS stylesheets are allowed to be loaded. `img-src` defines what images and favicons can be loaded. `worker-src` defines what worker scripts (e.g. `Worker`, `ServiceWorker` or `SharedWorker`) can be loaded and executed. `frame-src` defines what `<frame>` and `<iframe>` elements can be loaded. `child-src` defines what `<frame>`, `<iframe>` or workers can be loaded. `form-action` defines what URLs can be used for form submissions. Notice Consider adding the `upgrade-insecure-requests` directive to automatically upgrade HTTP requests to HTTPS, helping to prevent mixed content issues. Notice `unsafe-inline` in `style-src` allows inline styles. This is common and lower risk than inline scripts, but nonces or hashes provide stronger protection. Warning `unsafe-eval` allows `eval()` and similar dynamic code execution, which can be exploited for XSS. Consider refactoring code to avoid `eval()`.
server	cloudflare	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.
critical-ch	sec-ch-ua-bitness, sec-ch-ua-arch, sec-ch-ua-full-version, sec-ch-ua-mobile, sec-ch-ua-model, sec-ch-ua-platform-version, sec-ch-ua-full-version-list, sec-ch-ua-platform, sec-ch-ua, ua-bitness, ua-arch, ua-full-version, ua-mobile, ua-model, ua-platform-version, ua-platform, ua	On a browser's very first visit, it doesn't yet know which Client Hints the server wants. `Accept-CH` asks the browser to include them on future requests, but `Critical-CH` goes further: if the browser didn't send these hints, it must immediately retry the request with them included, before rendering anything. Every hint listed in `Critical-CH` must also appear in `Accept-CH`.
cross-origin-embedder-policy	require-corp	Controls whether this page can load resources (images, scripts, iframes) from other origins. When set, every cross-origin resource must explicitly opt in (via a `Cross-Origin-Resource-Policy` header or CORS) before this page can load it. This protects those other origins: by requiring their consent, the browser ensures their resources aren't exposed to Spectre-style timing attacks from this page. Setting this header (together with `Cross-Origin-Opener-Policy: same-origin`) is also required to enable powerful features like `SharedArrayBuffer` and high-resolution timers. `require-corp` means this page can only embed same-origin resources, or cross-origin resources that explicitly consent by sending a `Cross-Origin-Resource-Policy: cross-origin` header (or the equivalent CORS headers). Resources without that consent are blocked.
cross-origin-opener-policy	same-origin	Controls whether other pages can access this page's `window` object (and vice versa) when opened via `window.open()` or by navigating to a new page. Without this header, a malicious page could open your site and retain a reference to its `window`, enabling script-based attacks through the shared browsing context. Setting this to `same-origin` severs that link for cross-origin pages. Note: COOP governs top-level documents and popups, not iframes. Use `X-Frame-Options` or CSP `frame-ancestors` to control iframe embedding. `same-origin` isolates this page completely. Cross-origin pages that open this page (or are opened by it) will get `window.opener` set to `null` and cannot script each other. This is the strictest and most secure option.
cross-origin-resource-policy	same-origin	Controls which origins are allowed to load this resource (e.g. embed this image, load this script). This prevents other sites from hotlinking your resources and is how a resource signals its consent to be loaded by pages that use `Cross-Origin-Embedder-Policy`. `same-origin` means the resource can only be loaded by documents from the same origin.
origin-agent-cluster	?1	When set to `?1`, tells the browser to give this page its own isolated process or memory space, keyed by origin rather than site. This prevents pages on different subdomains (e.g. `sub.example.com` and `example.com`) from sharing a browsing context, improving security isolation at the cost of losing `document.domain` access between subdomains.
permissions-policy	accelerometer=(),camera=(),clipboard-read=(),clipboard-write=(),geolocation=(),gyroscope=(),hid=(),magnetometer=(),microphone=(),payment=(),publickey-credentials-get=(),screen-wake-lock=(),serial=(),sync-xhr=(),usb=(),xr-spatial-tracking=*	Controls which browser features and APIs (camera, microphone, geolocation, payment, USB, etc.) this page and its embedded iframes are allowed to use. Each feature is set to an allowlist of origins; an empty list `()` disables the feature entirely. This is a defense-in-depth measure: even if an attacker injects script via XSS, they cannot access the restricted APIs.
referrer-policy	same-origin	When a visitor navigates from one page to another page, browsers often pass along referrer information. The `Referrer-Policy` header controls how much referrer information a browser can share. This is important because private information can be embedded in the path or query string. `same-origin` means that the full URL (protocol, host, port, path and query string) is shared for same-origin requests. For cross-origin requests, no referrer information is shared at all.
server-timing	chlray;desc="a1b4fcff1ffbe57e"	Exposes server-side performance metrics (e.g. database query time, cache lookups, total processing time) to the browser. These metrics appear in the browser's DevTools Network tab, making it easier to diagnose slow responses without needing server-side log access.
x-content-type-options	nosniff	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.
x-frame-options	sameorigin	`X-Frame-Options` prevents this URL from being embedded in an `iframe`. This protects against clickjacking attacks. `sameorigin` allows this page to be displayed in an `iframe` on the same origin. This is the recommended setting.
report-to	{"group":"cf-nel","max_age":604800,"endpoints":[{"url":"https://a.nel.cloudflare.com/report/v4?s=6f4i6haj6zijuy%2bc6jxlvw6f6urojcpsdvxpe1ldhjq1vcj6rpp5s3ktu9ardb1d%2fiabblhornsrzgt9knr8fhd9iucr%2feozpamhlsh2n53ypvhntdd8fjqyif5hlb9aioroexkzogf7z2yw"}]}	The `Report-To` header defines where browsers should send error reports. It sets up named reporting endpoints that other headers (like `NEL` and `Content-Security-Policy`) reference when they need to send violation or failure data. `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 sent 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.
nel	{"report_to":"cf-nel","success_fraction":0.0,"max_age":604800}	The `NEL` (Network Error Logging) header tells browsers to report network-level failures (DNS errors, TCP timeouts, TLS problems) back to the server. This means you can detect when real users fail to reach your site, even though the failure happens before your server sees a request. `report_to` defines the reporting group that reports for this NEL policy will be sent to. The reporting group details are specified in the `Report-To` header. `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. `success_fraction` defines the sampling rate that should be applied to reports about successful network requests. Its value must be a number between 0.0 and 1.0: 0 means no successful requests should be reported, and 1 means that every successful request should be reported.
content-encoding	br	Specifies how the resource is compressed. Not to be confused with `Transfer-Encoding` which specifies how the data is transferred. `br` means that the data is compressed with `brotli`. 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.
cf-ray	a1b4fcff1ffbe57e-iad	The `cf-ray` header provides a unique identifier for each request through Cloudflare. It's useful for troubleshooting and tracking requests in Cloudflare logs.
strict-transport-security		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.
x-permitted-cross-domain-policies		missing Add a `X-Permitted-Cross-Domain-Policies` header to prevent Flash, Adobe Reader and other clients from sharing data across domains.