HTTP Headers Lookup

Inspect Server Responses with Our HTTP Headers Checker

Every time a browser requests a webpage, the server responds with invisible metadata called HTTP headers. Our HTTP Headers Lookup tool allows you to reveal this hidden layer of communication. Understanding these headers is critical for diagnosing loading issues, verifying security implementations, and optimizing SEO performance.

Whether you are a developer debugging a 500 error, an SEO specialist checking for canonical tags, or a security analyst verifying Strict-Transport-Security (HSTS) and Content-Security-Policy (CSP), this tool provides a raw, unfiltered view of the server's response.

Key Headers to Monitor

1. Status Codes: Verify if a page returns a 200 (OK), 301 (Redirect), or 404 (Not Found).
2. Cache-Control: Check how your server instructs browsers to cache content to improve load speeds.
3. Security Headers: Ensure headers like X-Frame-Options are active to prevent clickjacking attacks.
4. X-Robots-Tag: Detect hidden indexing directives that might be blocking search engines.

Frequently Asked Questions

How do I check HTTP headers of a website?

Simply enter the full URL (including https://) into the tool above and click "Lookup". The tool will attempt to fetch the URL and display the raw response headers returned by the server.

What are HTTP response headers and why are they important?

They are key-value pairs sent by the server before the actual page content. They control browser caching, security enforcement, compression (Gzip/Brotli), and provide information about the server software.

How can I view security headers of a website?

Run a lookup on your domain. Look for specific keys in the output list such as Content-Security-Policy, X-Content-Type-Options, and Referrer-Policy. Missing these can leave your site vulnerable.

What HTTP headers should I check for SEO?

Focus on the Status Code (ensure it's 200 for live pages), the Canonical Link header, and the X-Robots-Tag. These directly influence how Google crawls and indexes your content.

How do I analyze server response headers?

Use the output window to read the values. The "Server" header often reveals the technology stack (e.g., Nginx, Apache), while "Vary" tells you how the server handles content negotiation.