Free HTTP Headers Lookup Tool
Examine the exact HTTP response headers returned by a web server for any URL. Troubleshoot redirects, cookie settings, caching, and server response codes.
What are HTTP Response Headers?
Every time a browser requests a web page, the web server replies with the requested content and a set of HTTP response headers. These headers contain metadata that instruct the browser on how to handle, display, cache, and secure the web page. Checking your server's response headers is an essential step in verifying security policies, diagnosing redirect loops, and optimizing caching configurations.
The Importance of HTTP Security Headers
Modern security headers protect your website and visitors from attacks like Cross-Site Scripting (XSS), clickjacking, and packet sniffing. When auditing your HTTP headers, ensure the following keys are present and configured correctly:
- Strict-Transport-Security (HSTS): Forces the browser to connect exclusively using HTTPS, preventing downgrades to HTTP.
- Content-Security-Policy (CSP): Prevents unauthorized scripts from executing by restricting allowed source domains.
- X-Frame-Options (XFO): Prevents your site from being loaded inside an iframe on other websites, mitigating clickjacking attacks.
- Cache-Control: Dictates how long browser and proxy caches store your page assets, impacting performance.
For more optimization options, use our URL Redirect Checker to trace multi-hop paths, or test performance with the HTTP/2 Checker.
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