HTTP Header Analyzer

HTTP response headers control critical security behaviors — content security policies, frame embedding, HTTPS enforcement, and cross-origin access. This HTTP header analyzer audits your headers and scores them on security best practices, with specific fix snippets for Nginx, Apache, Express, and Cloudflare. Run an HTTP headers test in seconds by pasting the output of curl -I https://yoursite.com directly into the tool.

Unlike online scanners that require a live URL, this tool lets you analyze HTTP headers from staging environments, localhost, or curl output without exposing internal services to a third-party scanner. Everything runs in your browser; no data is sent anywhere. This makes it ideal for auditing pre-production environments, internal APIs, or any server you wouldn't expose to an external scanning service.

HTTP security headers are the first line of defense against a wide range of web attacks. Missing or misconfigured headers are one of the most common findings in security audits — and they're also among the easiest to fix. A few lines in your server config can close vulnerabilities that would otherwise require complex application-level code to address. The OWASP Top 10 and most security compliance frameworks (SOC 2, PCI DSS) explicitly require these headers.

Common misconfigurations that this HTTP header analyzer catches include: missing Strict-Transport-Security (HSTS) that leaves users vulnerable to SSL stripping attacks; no Content-Security-Policy or a policy with unsafe-inline that defeats XSS protection; absent X-Content-Type-Options: nosniff that allows MIME-type confusion attacks; and overly permissive CORS with Access-Control-Allow-Origin: * combined with credentials. Each of these has been exploited in real attacks against production sites.

To run an http headers test from the command line, use: curl -I https://example.com for a HEAD request (headers only), or curl -D - -o /dev/null https://example.com to capture headers from a GET request. You can also grab headers from your browser's DevTools Network tab — right-click any request, select "Copy response headers," and paste here. The tool strips the HTTP status line automatically.

Each security header protects against a specific class of attack. Strict-Transport-Security (HSTS) prevents protocol downgrade attacks and cookie hijacking. Content-Security-Policy (CSP) blocks cross-site scripting by whitelisting trusted content sources. X-Content-Type-Options prevents browsers from interpreting files as a different MIME type. X-Frame-Options (or the frame-ancestors CSP directive) blocks clickjacking. Referrer-Policy controls what URL information leaks in the Referer header. Permissions-Policy restricts access to browser APIs like camera, microphone, and geolocation.