Inspect HTTP response headers, security headers, cache configuration, and CORS settings for any URL — instantly and for free.
View all HTTP response headers returned by any server. Inspect content type, server software, powered-by headers, and custom headers at a glance.
Check for critical security headers like Content-Security-Policy, Strict-Transport-Security, X-Frame-Options, and X-Content-Type-Options.
Analyze caching configuration including Cache-Control, ETag, Expires, and Last-Modified headers. Optimize your site’s caching strategy.
Inspect Cross-Origin Resource Sharing headers. Verify Access-Control-Allow-Origin, allowed methods, and credentials configuration.
Detect HTTP redirects (301, 302, 307, 308) and see the full redirect chain. Identify redirect loops and unnecessary hops.
Review performance-related headers like Content-Encoding (gzip/brotli), Transfer-Encoding, Connection, and Keep-Alive settings.
Type or paste any website URL into the input field. Include the full URL with https:// for accurate results.
Hit the "Check Headers" button. Our servers will send a request to the URL and capture all response headers returned by the server.
See every response header in a clear table. Security headers are highlighted in green, and missing critical headers are flagged in red so you can fix them.
HTTP headers are the invisible backbone of every web interaction. They control how browsers cache your pages, whether your site is vulnerable to clickjacking or cross-site scripting, and how third-party services interact with your API. Yet most website owners never inspect them.
Security headers are your first line of defense against common web attacks. A missing Content-Security-Policy header means your site has no protection against XSS injection. Without Strict-Transport-Security, users could be silently downgraded from HTTPS to HTTP by a man-in-the-middle attacker. Our header checker flags these gaps instantly.
Cache headers directly impact your site's performance and SEO ranking. Misconfigured Cache-Control or missing ETag headers force browsers to re-download resources on every visit, slowing down page loads. Conversely, overly aggressive caching can serve stale content to your users.
For developers building APIs and single-page applications, CORS headers are a constant source of frustration. Our tool lets you verify Access-Control-Allow-Origin, allowed methods, and credentials settings without opening browser dev tools or writing curl commands.
HTTP headers are metadata sent between your browser and a web server with every request and response. They control caching, security, content type, authentication, and more. Response headers tell your browser how to handle the received content.
Checking HTTP headers helps you verify security configurations, debug caching issues, troubleshoot CORS errors, audit your site’s security posture, and ensure proper content delivery. Missing security headers can leave your site vulnerable to attacks like clickjacking and XSS.
The most critical security headers are Content-Security-Policy (CSP), Strict-Transport-Security (HSTS), X-Frame-Options, X-Content-Type-Options, and X-XSS-Protection. These headers protect against cross-site scripting, clickjacking, MIME sniffing, and man-in-the-middle attacks.
A missing security header means your website isn’t using that particular browser-side protection. For example, missing Strict-Transport-Security means browsers won’t enforce HTTPS, and missing X-Frame-Options means your site could be embedded in malicious iframes (clickjacking).
Cache-Control headers tell browsers and CDNs how to cache your content. Common directives include max-age (how long to cache), no-cache (always revalidate), no-store (never cache), and public/private (who can cache). Proper caching dramatically improves page load speed.
CORS (Cross-Origin Resource Sharing) headers control which websites can make requests to your server from a browser. The Access-Control-Allow-Origin header specifies allowed origins. Misconfigured CORS headers are a common source of frontend errors and can also create security vulnerabilities.
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