HTTP Headers Checker

Inspect HTTP response headers to analyze security policies, caching configuration, and server behavior.

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Important Security Headers

Strict-Transport-Security (HSTS)

Forces browsers to use HTTPS connections only.

Content-Security-Policy (CSP)

Prevents XSS attacks by controlling resource loading.

X-Frame-Options

Protects against clickjacking by controlling iframe embedding.

X-Content-Type-Options

Prevents MIME type sniffing attacks.

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How to Use HTTP Headers Checker

  1. Enter the URL of the website you want to analyze
  2. Click "Check Headers" to send a request
  3. Review all HTTP response headers returned by the server
  4. Check for security headers (CSP, HSTS, X-Frame-Options)
  5. Identify caching settings, server information, and redirects
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About HTTP Headers Checker

HTTP headers carry critical metadata between browsers and servers, controlling everything from security policies to caching behavior. Our HTTP Headers Checker reveals this hidden layer of web communication, helping developers optimize performance and security professionals audit configurations.

Security Headers Analysis

Modern web security relies heavily on HTTP headers to protect against common attacks:

  • Content-Security-Policy: Prevents XSS attacks by controlling resource loading sources
  • X-Frame-Options: Blocks clickjacking by controlling iframe embedding
  • Strict-Transport-Security: Forces HTTPS connections to prevent downgrade attacks
  • X-Content-Type-Options: Prevents MIME-type sniffing vulnerabilities
  • Referrer-Policy: Controls information shared when users navigate away
  • Permissions-Policy: Restricts browser feature access like camera or geolocation

Performance Optimization

Cache-Control and ETag headers determine how browsers store and revalidate resources. Properly configured caching headers can dramatically reduce server load and improve page speed. Our tool shows exactly what caching policies are in effect and helps identify optimization opportunities.

Debugging and Development

Server headers reveal technology stacks (Server, X-Powered-By), which can expose version information useful for security audits. Redirect chains and their headers help debug navigation issues. Cookie attributes visible in Set-Cookie headers affect session security and cross-site behavior.

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Frequently Asked Questions

What are HTTP headers and why check them?
HTTP headers are metadata sent with requests/responses: content type, caching rules, security policies, cookies, and more. Checking headers helps debug issues, verify security configuration, analyze caching, and understand how servers respond to requests.
What security headers should my site have?
Essential security headers: Content-Security-Policy (XSS protection), X-Frame-Options (clickjacking), X-Content-Type-Options (MIME sniffing), Strict-Transport-Security (HTTPS enforcement). Our tool checks for these and grades your security header implementation.
What do cache headers mean?
Cache-Control defines caching behavior: max-age (seconds to cache), no-cache (always revalidate), no-store (never cache). ETag and Last-Modified enable conditional requests. Proper caching improves performance. We analyze your cache configuration.
How do I check headers for different request methods?
We test GET (standard requests), HEAD (headers only), POST, and OPTIONS (CORS preflight). Different methods may return different headers, especially for APIs. Our tool lets you select request method and add custom headers to test.
What is the difference between request and response headers?
Request headers are sent FROM your browser (Accept, User-Agent, Authorization). Response headers come FROM the server (Content-Type, Set-Cookie, Cache-Control). Our tool shows both, highlighting which direction each header travels.
Why do I see different headers than expected?
Proxies, CDNs, and load balancers can modify headers in transit. Headers also vary by request method, authentication state, and user agent. Compare headers from different sources (direct vs CDN) to understand the full picture.