What is the HTTP Header Analyzer?

Every HTTP response a web server sends includes a set of headers — key-value pairs that travel alongside the response body and carry metadata about the content, the server, caching policy, security rules, and more. Browsers read and act on these headers silently; the HTTP Header Analyzer makes them visible.

Enter any URL and the tool fetches the server's response headers, displaying them in a readable format so you can inspect, debug, and evaluate how the server is configured.

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How to Use the Analyzer

1. Enter a URL — type or paste the full URL you want to inspect, including https://. Subdomains and paths are supported.
2. Fetch headers. The tool sends a request to the server and captures the response headers without downloading the full page body.
3. Read the results. Headers are displayed in a clean list with the header name and its value. Click any header name to see an explanation of what it does.

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Key Headers and What They Tell You

Content-Type — the MIME type of the response (e.g. text/html; charset=utf-8, application/json). Confirms the server is returning the format you expect and with the right character encoding.

Cache-Control — controls how and for how long the response can be cached by browsers and CDNs. Values like max-age=86400 mean the browser can reuse the cached response for 24 hours without re-fetching.

Server — identifies the web server software (e.g. nginx, Apache, cloudflare). Sometimes omitted or obscured for security reasons.

Strict-Transport-Security (HSTS) — tells browsers to only connect to this domain over HTTPS, even if a user types http://. A missing or misconfigured HSTS header means the site may be vulnerable to downgrade attacks.

X-Content-Type-Options — when set to nosniff, prevents browsers from guessing the content type and executing files as a different type than declared. Mitigates MIME-sniffing attacks.

X-Frame-Options — controls whether the page can be embedded in an <iframe>. DENY or SAMEORIGIN prevents clickjacking attacks.

Content-Security-Policy (CSP) — defines which sources of scripts, styles, images, and other resources the browser is allowed to load. A well-configured CSP significantly reduces XSS attack surface.

Access-Control-Allow-Origin — the CORS header that controls which origins can make cross-origin requests to the server. Relevant when debugging API requests from a browser.

Location — present in redirect responses (301, 302). Shows where the server is redirecting to — useful for tracing redirect chains.

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Common Use Cases

Security auditing — check whether a site has the recommended security headers in place: HSTS, CSP, X-Frame-Options, X-Content-Type-Options. Missing headers represent real vulnerabilities.

Cache debugging — verify that Cache-Control and Expires headers are set correctly for performance. Confirm that CDN caching is active or identify why content isn't being cached.

Redirect tracing — diagnose redirect loops or incorrect redirect targets by inspecting the Location header on 3xx responses.

Server configuration verification — confirm that a newly deployed server or CDN configuration is returning the expected headers after a change.

API debugging — check CORS headers on API responses when diagnosing why a browser-side request is being blocked.

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Privacy

Header requests are made directly to the target server. No URLs entered or headers retrieved are stored or logged.