HTTP Headers Lookup

Quickly fetch and inspect the raw HTTP response headers of any remote URL.

What are HTTP Headers?

HTTP headers let the client and the server pass additional information with an HTTP request or response. An HTTP header consists of its case-insensitive name followed by a colon (':'), then by its value.

Our HTTP Headers Lookup tool performs a secure HEAD request natively from our backend to the target URL, retrieving the server's response headers. This is a critical debugging step for developers to verify cache control rules, identify server software (e.g., Nginx, Apache), inspect cross-origin resource sharing (CORS) rules, and validate HTTP security headers.

Essential Security Headers to Monitor

  • Strict-Transport-Security (HSTS): Enforces secure (HTTP over SSL/TLS) connections to the server.
  • Content-Security-Policy (CSP): Prevents cross-site scripting (XSS), clickjacking, and other code injection attacks.
  • X-Frame-Options: Prevents your site from being framed and protects against clickjacking.