HTTP Header Checker
Analyze HTTP response headers and security configuration for any URL.
What is an HTTP Header Checker?
An HTTP header checker inspects the response headers returned by a web server when you request a URL. These headers contain important information about the server's configuration, security policies, caching behavior, content type, and more.
Why check HTTP headers?
- Verify security headers like HSTS, CSP, and X-Frame-Options are properly set
- Debug caching issues by inspecting Cache-Control and ETag headers
- Check CORS configuration for API endpoints
- Identify server software and technology stack
- Troubleshoot redirect and authentication issues
Frequently Asked Questions
What are HTTP security headers?
HTTP security headers are server response headers that tell browsers how to behave when handling your website. Key ones include Content-Security-Policy, X-Frame-Options, Strict-Transport-Security (HSTS), and X-Content-Type-Options.
What does Content-Security-Policy do?
Content-Security-Policy (CSP) controls which external resources — scripts, images, fonts, iframes — a page is permitted to load. It is one of the most effective defenses against cross-site scripting (XSS) attacks.
What is X-Frame-Options?
X-Frame-Options controls whether your page can be embedded in an iframe on another site. Setting it to DENY or SAMEORIGIN prevents clickjacking attacks where attackers overlay invisible UI elements on top of your page to trick users into clicking them.
Why should I check my site's HTTP headers?
Missing security headers leave your site vulnerable to clickjacking, XSS, MIME sniffing attacks, and other exploits. Regular header checks help you catch security gaps before attackers do, and many hosting providers and CDNs will not set them by default.