Website Tools

HTTP Headers Checker

View every HTTP response header a website sends.

Enter a domain to view its full HTTP response headers.

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JustChecker monitors your websites around the clock and alerts you the instant something changes.

What Is the HTTP Headers Checker?

HTTP response headers are metadata a server sends with every page: content type, caching rules, compression, cookies, security policies and server software. This tool fetches a URL and lists all of its response headers.

When to Use It

When debugging caching, CORS, redirects or compression.
To check which security headers a site sends.
To see which server software or CDN a site uses.

How to Use It

Enter a URL or domain.
Scan the list of headers and their values.

Understanding the Result

Useful headers to look for include Content-Type, Cache-Control, Content-Encoding (gzip or br), Strict-Transport-Security and Content-Security-Policy. Headers like cf-ray or x-amz-cf-id reveal a CDN.

Limitations

Headers can differ between pages, logged-in users and countries. For a scored review of security headers use the Security Headers Checker, and for caching the Cache Headers Checker.

Frequently Asked Questions

Headers describe metadata about the response - content type, caching rules, server software, cookie settings, security policies, and more - all sent alongside the actual page content but not visible in the rendered page itself.

Advertising a specific software version can make it slightly easier for an attacker to target known vulnerabilities in that exact version - many security-conscious setups deliberately suppress or genericize this header.

This tool shows every header your server sends, unfiltered; the Security Headers Checker specifically evaluates the subset of headers relevant to browser security policy (HSTS, CSP, X-Frame-Options, etc.) and scores them.

Some headers (like Date, or a caching-related ETag) are expected to change on every request by design - this doesn't indicate any instability, just normal, request-specific header behavior.

It tells the browser how to interpret the response body - as HTML, JSON, an image, plain text, etc. - an incorrect Content-Type can cause a browser to render or download content incorrectly even if the underlying data itself is fine.

Yes - caching headers (Cache-Control, Expires) directly control whether a browser can reuse a previously downloaded resource instead of re-fetching it, which can meaningfully speed up repeat visits.