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HTTP Header Inspector

Inspect complete HTTP response headers across every redirect hop, up to 10 redirects, instead of seeing only the final response. Detect missing HSTS, CSP, X-Content-Type-Options, clickjacking protection, and insecure cookie flags, with clickable header names linked to reference documentation.

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Tool Details

Inspect Every HTTP Response Header Across the Full Redirect Chain

When a website behaves unexpectedly, the problem is often hiding in the HTTP response headers rather than the page itself. Redirect loops, missing security headers, incorrect caching rules, cookies without protection flags, and misconfigured reverse proxies can all create issues that are difficult to spot from the browser UI alone.

The HTTP Header Inspector on CoolDev.Tools helps you inspect a URL in detail by fetching it, following redirects manually, and showing the complete response headers returned at every step.

Instead of showing only the final destination, the tool traces each redirect hop individually, up to 10 hops, so you can see exactly what happened along the way.

It also automatically checks for common web security issues, including:

  • Missing HSTS
  • Missing Content Security Policy
  • Missing X-Content-Type-Options
  • Cookies without Secure
  • Cookies without HttpOnly
  • Missing clickjacking protection

Every header name is also clickable, taking you directly to the relevant header reference documentation so you can understand what that header does and whether the value looks correct.

This makes the tool useful for developers, DevOps engineers, security teams, SEO professionals, and anyone troubleshooting production websites.

What Are HTTP Response Headers?

HTTP response headers are metadata sent by a web server along with the actual page, API response, image, or file.

They tell the browser how to handle the response.

For example, headers can control:

  • redirects
  • caching
  • security policies
  • cookies
  • content type
  • compression
  • browser behaviour

A response might contain headers like:

HTTP/1.1 301 Moved Permanently
Location: https://www.example.com/
Cache-Control: no-cache
Content-Type: text/html

The browser normally processes these silently.

An HTTP header inspector makes them visible so you can debug what the server is actually doing.

Why Inspecting Only the Final Response Is Not Enough

Many header-checking tools fetch a URL, automatically follow redirects, and show only the final response.

That can hide important problems.

Consider this chain:

http://example.com
→ https://example.com
→ https://www.example.com
→ https://www.example.com/home

If you only inspect /home, you may miss:

  • an unnecessary redirect
  • an HTTP-to-HTTPS misconfiguration
  • a temporary 302 where a permanent 301 was intended
  • cookies being set during an intermediate redirect
  • different security headers at different hops

The HTTP Header Inspector exposes every step.

Manual Redirect Tracing Up to 10 Hops

The tool follows redirects manually instead of letting the underlying HTTP client hide them.

For each hop, you can inspect:

  • HTTP status code
  • destination URL
  • Location header
  • complete response headers
  • security warnings

Redirects are followed for up to 10 hops, which helps prevent accidental infinite redirect loops from running endlessly.

This is especially useful while debugging:

  • HTTP to HTTPS redirects
  • www to non-www redirects
  • old URL migrations
  • CDN redirects
  • authentication flows
  • reverse proxy rules

Understanding HTTP Redirect Status Codes

Different redirect codes have different meanings.

301 Moved Permanently

A 301 tells clients and search engines that the resource has permanently moved.

Common uses:

  • HTTP to HTTPS migration
  • domain migration
  • permanent URL changes

302 Found

A 302 is generally used for temporary redirects.

It tells clients that the current redirect may change later.

307 Temporary Redirect

A 307 is similar to 302, but it explicitly preserves the original HTTP method.

For example, a POST remains a POST.

308 Permanent Redirect

A 308 is the permanent equivalent of 307.

It preserves the HTTP method while indicating that the destination has permanently changed.

Inspect Complete Headers at Every Hop

Each response in the redirect chain shows the complete set of headers returned by the server.

This can include headers such as:

Cache-Control
Content-Type
Content-Length
Content-Encoding
ETag
Last-Modified
Location
Server
Set-Cookie
Strict-Transport-Security
Content-Security-Policy
X-Content-Type-Options

Seeing these values side by side is often the fastest way to identify infrastructure problems.

Clickable Header Reference Documentation

HTTP headers can become quite technical, especially when you encounter one you haven't worked with before.

Every header name in the inspector is clickable and links directly to the corresponding header reference documentation.

This means you can inspect a response and immediately learn:

  • what the header controls
  • common values
  • security implications
  • typical use cases

It turns the inspector into both a debugging tool and a practical HTTP reference.

Automatic Web Security Checks

The tool doesn't simply display headers.

It also analyses the response and highlights common security gaps automatically.

This saves you from manually remembering every recommended header.

Missing HSTS Detection

HSTS, or HTTP Strict Transport Security, tells browsers that a website should only be accessed over HTTPS.

The header usually looks like:

Strict-Transport-Security: max-age=31536000; includeSubDomains

Without HSTS, users may initially connect over insecure HTTP before being redirected to HTTPS.

The inspector flags responses where HSTS is missing.

Missing Content Security Policy

A Content Security Policy (CSP) helps reduce risks such as cross-site scripting by controlling which resources a browser is allowed to load.

Example:

Content-Security-Policy: default-src 'self'

CSP configuration can become much more detailed depending on the application.

The tool warns when a CSP header is missing so you can investigate whether one should be configured.

Missing X-Content-Type-Options

The recommended header is:

X-Content-Type-Options: nosniff

It tells browsers not to guess or "sniff" content types when the server has already declared one.

This helps reduce certain content interpretation vulnerabilities.

The inspector automatically flags its absence.

Detect Cookies Without Secure

A secure cookie may look like:

Set-Cookie: session=abc123; Secure

The Secure flag tells the browser to send the cookie only over HTTPS.

Session or authentication cookies without this flag can create unnecessary security exposure.

The inspector checks Set-Cookie headers and warns when the Secure flag is missing.

Detect Cookies Without HttpOnly

The HttpOnly cookie attribute prevents normal client-side JavaScript from reading a cookie.

Example:

Set-Cookie: session=abc123; Secure; HttpOnly

This is especially important for session cookies because it reduces exposure if malicious JavaScript executes on the page.

The tool flags cookies that are set without HttpOnly.

Check Clickjacking Protection

Clickjacking is an attack where a website is loaded inside another page's frame and users are tricked into clicking something they did not intend to interact with.

Protection can be implemented using headers such as:

X-Frame-Options: DENY

or through CSP directives such as:

Content-Security-Policy: frame-ancestors 'none'

The inspector warns when obvious clickjacking protection is missing.

Common Use Cases for the HTTP Header Inspector

Debugging Redirect Chains

Check whether URLs redirect correctly and whether unnecessary hops exist.

HTTPS Migration

Verify that:

http://

correctly redirects to:

https://

and inspect whether HSTS is configured.

CDN and Reverse Proxy Debugging

Compare headers added by:

  • Cloudflare
  • Nginx
  • Apache
  • load balancers
  • application servers

Cookie Troubleshooting

Inspect session cookies, domain settings, and security flags.

Security Reviews

Quickly identify missing baseline security headers.

SEO Migration Checks

Confirm permanent redirects during domain or URL restructuring.

How to Use the HTTP Header Inspector

Step 1: Enter a URL

Paste the page or endpoint you want to inspect.

Example:

https://example.com

Step 2: Run the Inspection

The tool fetches the URL and captures the response.

Step 3: Follow the Redirect Chain

If a redirect occurs, the tool manually fetches the next URL and records that response separately.

This continues for up to 10 hops.

Step 4: Inspect Every Header

Review the complete response headers returned at each stage.

Step 5: Review Security Warnings

Check the automatic findings for missing security headers or insecure cookies.

Step 6: Open Header Documentation

Click any header name when you want to understand its behaviour in more detail.

Why This Is Useful for Developers and DevOps Teams

A production request often passes through several layers before reaching an application:

Browser
→ CDN
→ Load Balancer
→ Nginx
→ Application

Each layer may:

  • add headers
  • remove headers
  • create redirects
  • modify cookies
  • change caching behaviour

Seeing the complete HTTP chain makes it easier to identify which layer introduced the problem.

For example, if your application sets HSTS but the public response does not contain it, a proxy configuration may be altering the header before it reaches visitors.

Frequently Asked Questions (FAQs)

What does an HTTP header inspector do?

It fetches a URL and displays the HTTP response headers returned by the server, helping you debug redirects, caching, cookies, security policies, and other web behaviour.

Does the tool follow redirects?

Yes. It follows redirects manually and shows each individual response for up to 10 hops.

Why is seeing every redirect hop useful?

Intermediate responses may contain incorrect status codes, cookies, missing security headers, or unnecessary redirects that are hidden when only the final response is shown.

What security headers does the tool check?

It checks for common issues including missing HSTS, CSP, X-Content-Type-Options, clickjacking protection, and insecure cookie attributes.

What does the Secure cookie flag do?

It prevents the browser from sending the cookie over unencrypted HTTP connections.

What does HttpOnly do?

It prevents ordinary browser JavaScript from accessing the cookie, which is particularly useful for protecting session cookies.

Is a missing security header always a vulnerability?

Not necessarily. Security requirements depend on the application and architecture. The warnings are intended to highlight areas worth reviewing rather than automatically prove that a site is vulnerable.

Conclusion

HTTP headers reveal what is actually happening between a server and a browser, but they are easy to overlook when debugging a website from the visible page alone.

The HTTP Header Inspector on CoolDev.Tools gives you a detailed view of that communication by tracing up to 10 redirect hops manually and displaying the complete response headers at every stage.

With clickable header documentation and automatic checks for HSTS, CSP, X-Content-Type-Options, cookie security flags, and clickjacking protection, the tool makes it easier to troubleshoot web infrastructure, redirects, cookies, and baseline security configuration from one place.

Whether you're fixing an Nginx redirect, checking a CDN configuration, reviewing an HTTPS migration, or investigating production headers, this inspector helps turn an otherwise invisible request chain into something you can actually reason about.