🌐 HTTP header confirmation

HTTP header information and device information sent by the browser can be checked in real time.

Browser and device information

Usage and Application Examples

  • Check the User-Agent your browser is sending
  • Check screen resolution and window size (for testing responsive design)
  • Check network connection information (for debugging purposes)
  • Understanding device hardware information

What is HTTP Headers?

HTTP Headers are metadata sent with every web request, containing vital information about your browser, device, and connection. This tool displays headers your browser is sending—including User-Agent, accept languages, screen resolution, and more. Understanding these headers helps developers debug compatibility issues, verify correct browser detection, and ensure proper content negotiation between client and server.

How to Use

Simply visit the HTTP Headers Checker tool—no setup required. The page immediately detects and displays all HTTP headers transmitted by your browser to the web server. Each header shows the parameter name and its current value. You can review your User-Agent string (browser type and OS), language preferences (Accept-Language), content encoding support, device pixel ratio, and other technical details. The tool updates automatically as your browser settings change. Copy headers for documentation or debugging purposes.

Use Cases

• Browser Compatibility Testing: Verify your User-Agent is recognized correctly by web servers and confirms you're using the expected browser version and operating system.
• Device Detection Debugging: Check if your actual screen resolution, device pixel ratio, and viewport dimensions match what a website's JavaScript detection logic identifies.
• Language Negotiation: Confirm your browser's Accept-Language header reflects preferred languages; useful when testing multi-language site behavior or diagnosing why wrong-language content appears.
• Mobile vs Desktop Detection: Quickly verify whether your browser is identified as mobile, tablet, or desktop—critical for testing responsive designs and detecting outdated user-agent strings.

Tips & Insights

HTTP headers are fundamental to web standards. The User-Agent header sometimes becomes outdated or incorrect after browser updates; this tool instantly confirms the actual string servers receive. Understanding Accept-Encoding headers helps optimize content delivery (gzip compression). The Accept header reveals what content types your browser prefers. Some web servers enforce header validation; use this tool to confirm all required headers are present and correctly formatted before troubleshooting server-side problems.

Frequently Asked Questions

What is the HTTP Header Verification Tool?

This tool allows you to check the User-Agent, language settings, screen size, and other information sent by your browser.

Is your privacy secure?

Yes. All information displayed is only retrieved and displayed within the browser and is not transmitted externally.

What are HTTP headers?

Meta information sent and received in the communication between the browser and the server. It includes content type, cache settings, security policies, etc.

What HTTP headers are frequently checked?

Content-Type (content type), Cache-Control (cache settings), and X-Frame-Options (anti-clickjacking) are often checked.

Where can I find a description of each item?

Hover the mouse over the "?" icon next to each header name to see a tooltip description. icon next to each header name displays a tooltip with an explanation. A brief explanation is also displayed below the header name, so even beginners can quickly understand the meaning of each item.

What are the common types of HTTP headers?

The main HTTP headers include Content-Type (media type specification), Cache-Control (cache control), Authorization (authentication information), Content-Security-Policy (security policy), Strict- Transport-Security (HTTPS enforcement), and Access-Control-Allow-Origin (CORS setting).

Why do HTTP headers matter for web developers?

HTTP headers control crucial aspects like caching, security (CORS, CSP), content type, and compression. Understanding headers helps optimize performance, debug browser issues, and implement proper security policies. Developers use header information to ensure their sites work correctly across different browsers and devices.

Can I check HTTP headers from external websites I visit?

This tool shows headers from your current connection to the tool's server, which reflect your browser's configuration. To check headers from external websites, you would need to use browser developer tools (F12 → Network tab) or command-line tools like curl or wget. This limitation protects privacy by preventing arbitrary requests to third-party servers.

How do HTTP headers affect my website's performance?

Headers like Cache-Control, Content-Encoding, and Content-Length directly impact loading speed. For example, proper caching headers allow browsers to store resources locally, reducing repeat visits' load time significantly. Compression headers (gzip) also reduce file sizes transmitted over the network.

What information can HTTP headers reveal about security?

Headers like X-Frame-Options, Content-Security-Policy, and Strict-Transport-Security protect against clickjacking, XSS, and man-in-the-middle attacks. The absence of these security headers indicates vulnerability. Reviewing your headers helps identify security gaps and ensure best practices are implemented.

How do browsers use HTTP headers to decide what to cache?

Browsers read the Cache-Control header to determine if resources should be stored and for how long (max-age parameter). The Expires header provides an alternative way to specify expiration time. When you revisit a site, the browser checks these headers to decide whether to load fresh data or use cached versions.

Do HTTP headers impact SEO rankings?

Yes, headers like Content-Type, hreflang (in HTTP form), and X-Robots-Tag can affect SEO. Proper charset headers ensure content displays correctly, which impacts user experience and rankings. Search engines also use certain headers to understand your site's structure and mobile compatibility.