HTTP headers lookup

Get all the HTTP headers that an URL returns for a typical GET request.

Tool: HTTP Headers Lookup
Type: Server Analysis

HTTP headers lookup

Lookup HTTP Headers
Enter the complete URL including https://
Key Features
  • View all HTTP headers
  • Server information detection
  • Security headers analysis
  • Real-time lookup
  • No registration required

Common HTTP Headers Explained

Header Purpose Example Value
Content-Type Specifies media type of response text/html; charset=UTF-8
Server Information about server software nginx/1.24.0
Set-Cookie Sends cookies to client sessionid=abc123; Path=/
Cache-Control Specifies caching behavior public, max-age=3600
Content-Security-Policy Prevents XSS attacks default-src 'self'
X-Frame-Options Prevents clickjacking SAMEORIGIN
Strict-Transport-Security Forces HTTPS connection max-age=31536000
Access-Control-Allow-Origin Allows cross-origin requests * or domain

How to Use

1
Enter URL

Paste any website URL

2
Click Lookup

Submit the form

3
View Results

See all HTTP headers

4
Analyze

Review headers info

Important Security Headers

Strict-Transport-Security

Forces browsers to use HTTPS connections. Protects against SSL strip attacks and ensures secure communication.

Content-Security-Policy

Prevents XSS attacks by controlling which resources can be loaded. Specifies trusted sources for scripts, styles, and more.

X-Frame-Options

Prevents clickjacking attacks by controlling if page can be embedded in frames on other sites.

X-Content-Type-Options

Prevents MIME type sniffing attacks. Ensures browser respects Content-Type header.

Perfect For

Web Developers

Debug HTTP headers and understand server responses for web application development.

Security Audits

Check security headers to ensure proper security configurations and protections.

System Admins

Monitor server configuration and verify HTTP header settings across websites.

SEO Analysis

Analyze cache headers and server responses for SEO optimization.

Why Choose Our Tool?

⚡
Instant Results

Real-time header lookup

📊
All Headers

Complete header list

🔍
Detailed Info

Easy to understand format

🌍
Any Website

Check any public URL

📱
Mobile Friendly

Works everywhere

🆓
100% Free

No registration

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Complete Guide to HTTP Headers

Understanding HTTP Headers

HTTP headers are metadata sent with HTTP requests and responses that provide important information about the communication. They control caching, security, content type, and more. Understanding headers is essential for web developers, system administrators, and security professionals. Our HTTP Headers Lookup tool helps you view and analyze headers from any website instantly.

Types of HTTP Headers

  • Request Headers: Sent by client to server (User-Agent, Accept, Cookie)
  • Response Headers: Sent by server to client (Set-Cookie, Cache-Control, Server)
  • Entity Headers: Describe the body of message (Content-Type, Content-Length)
  • General Headers: Apply to both requests and responses (Date, Connection)

Why HTTP Headers Matter

HTTP headers control critical functions: caching policies reduce server load, security headers prevent attacks like XSS and clickjacking, content negotiation enables proper content delivery, and authentication headers verify user identity. Properly configured headers improve performance, security, and user experience.

Security Headers You Should Know

Strict-Transport-Security: Forces HTTPS and prevents man-in-the-middle attacks. Content-Security-Policy: Prevents XSS attacks by controlling resource loading. X-Frame-Options: Prevents clickjacking by controlling frame embedding. X-Content-Type-Options: Prevents MIME-sniffing attacks. Check these headers on your website to ensure proper security configuration.

Performance Headers for Optimization

Cache-Control: Specifies caching directives and duration. Expires: Sets absolute expiration date/time. ETag: Enables conditional requests to save bandwidth. Vary: Indicates which headers affect cache. Proper cache headers significantly reduce server load and improve page load times.

Pro Tip: Use this tool regularly to audit your website's HTTP headers. Missing security headers could expose your site to vulnerabilities.

Frequently Asked Questions

HTTP headers are metadata sent with HTTP requests and responses. They provide information about the communication, control caching, security, and content negotiation.
Check headers to verify security configuration, debug issues, optimize performance, and ensure proper caching policies.
Server header reveals information about the web server software. Security best practice: minimize or hide this header to reduce vulnerability exposure.
Cache-Control header specifies caching directives. ETag and Last-Modified enable conditional requests. Proper headers reduce server load and bandwidth.
Yes! Security headers like CSP, X-Frame-Options, and HSTS are critical for preventing XSS, clickjacking, and other attacks.
Yes! Check headers for any publicly accessible website. This tool queries live HTTP responses from servers.
Missing headers might indicate: not configured, intentionally removed for security, or filtered by intermediary servers/CDNs.
Yes! Our HTTP Headers Lookup is completely free with no hidden fees, premium features, or registration requirements.

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