Paste any URL to instantly analyze its HTTP headers. See security headers, caching directives, cookies, CORS policies, and more. Debug performance and SEO issues fast.
Last updated: May 2026
Enter a full URL including https://
HEAD fetches headers only and is faster. GET downloads the full response.
What we check
Your header report will appear here
Enter a URL to inspect its security, caching and server headers.
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HTTP headers are key-value pairs sent between a web browser (or client) and a web server during a request-response cycle. They carry metadata about the request or response: content type, caching rules, authentication tokens, security policies, and more. Our HTTP Header Checker tool lets you inspect these headers for any URL, helping you debug issues, verify security configurations, and understand how websites handle your data.
Security headers can reveal risks and performance issues on the modern web.
Verify whether important security headers like CSP, HSTS, and X-Frame-Options are present. Missing headers can create vulnerabilities.
HSTS and similar headers block basic attacks
Headers like Cache-Control and Compression can strongly influence performance. Optimize them for faster load times.
XSS has stayed among OWASP's top risks for years
Sometimes the problem is in header configuration. Quickly identify missing or incorrect headers.
Clickjacking hits banks, social networks, and SaaS dashboards
X-Content-Type-Options: nosniff tells the browser to trust the Content-Type the server declared and not try to guess. Without this header, an attacker who can upload a file labeled as an image can sometimes get the browser to execute it as JavaScript.
One line of config blocks an entire attack class
Referrer-Policy controls how much URL data the browser leaks to other origins when users click outbound links. A strict policy like strict-origin-when-cross-origin prevents sensitive query parameters, session tokens, or internal admin paths from leaking to third-party analytics and ad networks.
GDPR and CCPA actively penalize accidental data leakage
Permissions-Policy (formerly Feature-Policy) restricts which browser APIs your origin and embedded iframes can access. Disabling camera, microphone, geolocation, and payment APIs you do not use eliminates entire categories of supply-chain and third-party exploit risk.
Minimize the API surface attackers can reach
Caching and compression headers can make a site feel 5x faster with no code changes. Here is how the most important ones work.
These are the most frequent header misconfigurations we see when scanning sites. Each one is a quick win.
Missing HSTS
Allows SSL stripping on public Wi-Fi networks
CSP with unsafe-inline
Defeats the main purpose of Content-Security-Policy
Cache-Control: no-store on static assets
Wastes bandwidth and slows repeat visits
Verbose X-Powered-By
Leaks framework version to attackers for free
Missing Content-Encoding
Sends uncompressed HTML, hurting LCP and SEO
No Vary: Accept-Encoding
Can serve compressed bytes to clients that cannot decode them
The HTTP Header Checker is a free tool that helps you analyze and debug various aspects of your website.
Yes, this tool is completely free with no signup required.
Simply enter your URL and our tool will analyze it and show you the results.
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