HTTP Headers Viewer
Free online HTTP response headers checker tool
What are HTTP Headers?
HTTP headers are key-value pairs sent between a client and server with every HTTP request and response. Response headers contain metadata about the server, content type, caching policies, security settings (CSP, HSTS), cookies, and more. Inspecting headers is essential for debugging web applications and verifying security configurations.
How to Inspect HTTP Headers
Enter a URL and click Fetch Headers. The tool sends a request and displays all response headers. Look for security headers (Content-Security-Policy, X-Frame-Options), caching headers (Cache-Control, ETag), and content headers (Content-Type, Content-Length).
▶What security headers should every website have?
Important security headers include: Content-Security-Policy (CSP), Strict-Transport-Security (HSTS), X-Content-Type-Options: nosniff, X-Frame-Options, and Referrer-Policy.
▶Why did the header fetch fail?
Common reasons include: the URL is incorrect, the server is down, or the target server blocks cross-origin requests (CORS). Some servers may also block requests from automated tools.
▶Can I see request headers too?
This tool shows the response headers from the server. To see request headers, use your browser's Developer Tools Network tab.
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