HTTP headers lookup

Every time you visit a website, an invisible conversation takes place between your browser and the web server. This conversation is powered by HTTP Headers—snippets of data that contain critical instructions and information about the webpage you're requesting. Our HTTP Headers Lookup tool allows you to listen in on this conversation. It fetches and displays the full list of HTTP response headers for any URL you provide.

This is an essential diagnostic tool for web developers, system administrators, and SEO professionals. It gives you a direct, under-the-hood look at how a server is configured and how a webpage is being delivered, helping you debug issues, optimize performance, and improve your technical SEO.

What Are HTTP Headers?

Think of visiting a website like receiving a package. The content of the webpage (the text, images, etc.) is the "body" or the actual item inside the package. The HTTP Headers are like the shipping label and instructions written on the outside of the box. They are key-value pairs of metadata that tell the browser how to handle the content.

When you enter a URL, our tool's server sends a "request" to that URL's server. The server then sends back a "response." Our tool shows you the headers from that server response, which can include:

• Status Code: The single most important piece of information. It tells you the outcome of the request (e.g., 200 OK, 301 Moved Permanently, 404 Not Found, 500 Internal Server Error).
• Content-Type: Tells the browser what kind of content it's receiving (e.g., text/html for a webpage, image/jpeg for a picture).
• Server: Identifies the web server software being used (e.g., Apache, Nginx, Cloudflare).
• Cache-Control: Gives the browser specific instructions on how long it should "remember" or cache this file, which is critical for site speed.
• Content-Encoding: Shows if the content is being compressed to save bandwidth (e.g., gzip or br).
• Set-Cookie: Instructs the browser to set a tracking cookie for the site.
• Last-Modified: The date the file was last changed on the server.

Practical Uses: Who Needs to Check HTTP Headers?

Inspecting HTTP headers is a fundamental task for diagnosing and optimizing any website.

For Web Developers and System Administrators ⚙️

This is the ultimate debugging tool. Developers use it to:

• Verify Server Configuration: Are the caching and compression headers set correctly? Is the server identifying itself as expected?
• Debug API Responses: Check the status codes and content types of API endpoints to ensure they are functioning correctly.
• Analyze Security: Inspect for the presence of important security headers like Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security.

For SEO Professionals 📈

Technical SEO relies heavily on the information found in HTTP headers. SEOs use this tool to:

• Audit Redirects: Check if a redirect is a 301 (Permanent) or a 302 (Temporary). Using the wrong type can be devastating for search rankings, and this tool gives you a definitive answer.
• Troubleshoot Crawl Errors: Quickly identify if a URL is returning a 404 Not Found error or a server error (5xx codes), which can prevent Google from indexing your pages.
• Check Canonicalization: Look for the Link header, which can be used to specify a canonical URL, helping to resolve duplicate content issues.

Frequently Asked Questions (FAQ) about HTTP Headers

What is the most important header to look at?

The Status Code is always the first thing you should check. It gives you the immediate result of the request. A 200 OK means everything is working. A 3xx code means there's a redirect. A 4xx code means there's a client-side error (like a page not found). A 5xx code means there's a server-side error.

Why can't I just see this information in my browser?

This information is transmitted "behind the scenes" with every page you load. While you can find it by digging into your browser's Developer Tools (usually by pressing F12), our tool provides a much faster, cleaner, and more direct way to see just the headers for any URL without any other clutter.

Is it safe to use this tool?

Yes, it's completely safe. When you enter a URL, our server makes the request on your behalf, just like a normal browser would. Your own computer and IP address are never directly connected to the target server. It's simply a way to observe a standard, public web transaction.