Is this HTTP headers lookup really free?

Yes. You can run as many lookups as you need without creating an account or paying anything.

Why are my response headers different from what I see in Chrome DevTools?

Browsers sometimes modify headers or hide certain network-level details for security reasons. Extensions like adblockers also strip headers locally. This tool shows the raw response exactly as the server sent it, before the browser applies its own processing.

Does it work for local URLs or intranet addresses?

No. The tool runs on our servers, so it can only reach public IP addresses and domain names. It cannot resolve localhost, 127.0.0.1, or private RFC 1918 addresses on your internal network.

How do I check POST request headers with this?

You cannot. This tool strictly performs GET requests to fetch the initial resource state. If you need to inspect headers for a POST request, you need to use a local API client like curl or Postman.

What happens if the URL returns a 404 or 500 error?

You still get the headers. The tool captures the response regardless of the status code. Seeing the headers on a 500 error is often exactly what you need to debug a server crash.

HTTP headers lookup

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Paste a URL to see the HTTP response headers a server returns. This free HTTP headers lookup needs no signup and shows the exact payload your browser gets.

Mechanics of an http headers lookup

You type a URL. The tool fires a GET request and captures the raw response before the browser parses it. You see the status line, like HTTP/1.1 200 OK, followed by the exact key-value pairs the origin server sent. It shows you the unvarnished truth of the network transaction.

Browsers hide this stuff. They process Content-Type to render the page, check Cache-Control to decide if they should revalidate, and silently drop headers you might actually care about. An online HTTP headers lookup strips away that rendering layer. You get the raw text exactly as it crossed the wire, including duplicate headers that browsers often merge into a single comma-separated string.

When you need to check response headers

Debugging caching issues is the most common reason you will use this. If your CDN is serving stale assets, you need to verify the Cache-Control and ETag headers coming from the origin. You might also need to confirm a 301 Moved Permanently redirect is actually hitting the client, rather than a JavaScript redirect masking a server misconfiguration.

Security headers are another big one. You want to know if the server is actually sending Strict-Transport-Security or X-Content-Type-Options. Seeing them in the raw response proves your reverse proxy or load balancer is injecting them correctly. It is the only way to verify your infrastructure config without guessing.

Verify CDN caching rules and Vary headers.
Confirm security headers like Content-Security-Policy are present.
Inspect Set-Cookie attributes for Secure and HttpOnly flags.
Check CORS headers like Access-Control-Allow-Origin during API debugging.

Limits and edge cases of this tool

This tool performs a standard GET request. It will not execute JavaScript. If a page relies on client-side rendering to set cookies or trigger redirects, you will not see those actions here. You are seeing the initial server response, not the final state of a single-page application after React or Vue finishes booting. If the site uses a service worker to intercept and rewrite requests, this tool will not reflect that either.

It also does not follow redirects by default in a way that shows you the final destination headers in a single view. You get the headers for the exact URL you pasted. If that URL returns a 302, you see the 302 and its Location header. You have to manually paste the new URL to see the next hop.

How to use the http headers lookup

Paste the full URL into the input field.
Click the lookup button to send the request.
Read the HTTP status code at the top of the results.
Scroll through the response headers to find your target keys.
Copy the raw header block if you need to paste it into a bug report.

Common HTTP response headers explained

Here is a quick reference for the headers you will see most often in the results.

Header Name	Purpose	Example Value
Content-Type	Tells the client the media type of the resource	text/html; charset=utf-8
Cache-Control	Directives for caching mechanisms along the request chain	max-age=3600, public
Set-Cookie	Sends cookies from the server to the user agent	session_id=abc123; Path=/; HttpOnly
Strict-Transport-Security	Forces the browser to communicate via HTTPS only	max-age=31536000; includeSubDomains
X-Frame-Options	Indicates whether a page can be shown in a frame	DENY

Frequently asked questions

Is this HTTP headers lookup really free?: Yes. You can run as many lookups as you need without creating an account or paying anything.
Why are my response headers different from what I see in Chrome DevTools?: Browsers sometimes modify headers or hide certain network-level details for security reasons. Extensions like adblockers also strip headers locally. This tool shows the raw response exactly as the server sent it, before the browser applies its own processing.
Does it work for local URLs or intranet addresses?: No. The tool runs on our servers, so it can only reach public IP addresses and domain names. It cannot resolve localhost, 127.0.0.1, or private RFC 1918 addresses on your internal network.
How do I check POST request headers with this?: You cannot. This tool strictly performs GET requests to fetch the initial resource state. If you need to inspect headers for a POST request, you need to use a local API client like curl or Postman.
What happens if the URL returns a 404 or 500 error?: You still get the headers. The tool captures the response regardless of the status code. Seeing the headers on a 500 error is often exactly what you need to debug a server crash.