SSLFREE

HTTP Header Checker

Enter a URL to check its HTTP response headers.

Understanding HTTP Headers

HTTP headers are key-value pairs of information transferred between a web client (like your browser) and a server. They carry crucial data about the request or the response, such as content type, caching policies, and security settings. Analyzing these headers is vital for debugging, optimizing performance, and enhancing website security.

Why Use an HTTP Header Checker?

This tool is essential for developers, security professionals, and SEO specialists to ensure a website is configured correctly and securely.

Analyze Security Configurations

Verify the implementation of important security headers like Content-Security-Policy (CSP), Strict-Transport-Security (HSTS), and X-Frame-Options to protect against common web vulnerabilities.

Debug Redirects and Caching

Inspect headers like `Location`, `Cache-Control`, and `Expires` to troubleshoot redirection loops and ensure your caching strategy is working as intended.

Check Server Information

See what server software and technologies are being reported by the server, which can be useful for compatibility checks and security assessments.

Verify Third-Party Integrations

Confirm that headers required by CDNs, analytics platforms, or other third-party services are being correctly sent by your server.

Frequently Asked Questions

The CSP header is a powerful security feature that helps prevent Cross-Site Scripting (XSS) and other code injection attacks. It allows you to specify which sources of content (scripts, styles, images) are trusted and can be loaded by the browser.

HSTS tells browsers that they should only ever communicate with your site using a secure HTTPS connection. This prevents downgrade attacks and cookie hijacking by ensuring all future connections are encrypted, even if a user types `http://` in the address bar.

This can happen if your website is behind a reverse proxy, load balancer, or Content Delivery Network (CDN) like Cloudflare or AWS CloudFront. These services often add or modify the `Server` header, so what you see might be the server of the intermediary service, not your origin server.