HTTP Header Checker
Inspect HTTP headers of a given URL request/response to debug caching, security, and SEO issues. Analyze response headers for performance optimization and security best practices.
HTTP Header Best Practices
🔒 Security Headers
Strict-Transport-Security: Enforces HTTPS connections
Content-Security-Policy: Prevents XSS attacks
X-Frame-Options: Prevents clickjacking
X-Content-Type-Options: Prevents MIME sniffing
Referrer-Policy: Controls referrer information
⚡ Performance Headers
Cache-Control: Controls caching behavior
ETag: Enables conditional requests
Content-Encoding: Enables compression
Keep-Alive: Reuses connections
Server-Timing: Provides performance metrics
🎯 SEO Headers
Content-Type: Specifies media type and charset
X-Robots-Tag: Controls search engine indexing
Link (canonical): Prevents duplicate content
Status Codes: 2xx for success, avoid 4xx/5xx
💾 Caching Headers
max-age: Sets cache expiration time
no-cache: Forces revalidation
no-store: Prevents caching
must-revalidate: Forces fresh validation
Sample URLs to Test
How to Check Real Headers
🌐 Browser DevTools
- Press F12 to open DevTools
- Go to Network tab
- Visit the website
- Click on the first request
- Check Response Headers
💻 Command Line (curl)
curl -I https://example.com
Shows all response headers including security and caching directives.
🔧 Online Tools
- • HTTPie Online
- • Postman
- • Security Headers
- • GTmetrix
- • WebPageTest
Common Header Issues
❌ Common Problems
- • Missing security headers (HSTS, CSP, X-Frame-Options)
- • No cache control headers
- • Incorrect Content-Type or missing charset
- • Exposing server information
- • Missing compression headers
- • Improper CORS configuration
- • Weak referrer policies
- • Missing viewport meta for mobile
✅ Quick Fixes
- • Add security headers via server config
- • Implement proper cache-control directives
- • Enable gzip/brotli compression
- • Set appropriate max-age values
- • Use ETag for conditional requests
- • Configure proper CORS headers
- • Remove server version headers
- • Test headers regularly
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