HTTP Header Checker – Inspect Response Headers (HTTP/2 & HTTP/3)
Analyze HTTP response headers, security, caching, and CORS policies with detailed insights.
HTTP Header Inspector
How to check HTTP headers online?
Analyze HTTP response headers with our comprehensive header checker. Inspect security headers, caching policies, CORS settings, and performance optimizations. Perfect for web development, security auditing, and performance analysis.
Features
- Inspect HTTP response headers in real-time
- Analyze security headers (HSTS, CSP, X-Frame-Options)
- Check caching policies and compression
- Evaluate CORS configuration
- Support for HTTP/1.1, HTTP/2, and HTTP/3
- Follow redirect chains with detailed analysis
How to use
- Enter the URL you want to check in the input field
- Select the HTTP method (HEAD or GET)
- Configure advanced options if needed (redirects, custom headers)
- Click 'Check Headers' to analyze the response
- Review the security, caching, and CORS analysis
- Use 'Copy cURL' to get the command-line equivalent
Tips & Best Practices
- Double-check URLs and hostnames before running network lookups.
- Results may vary based on DNS propagation and network conditions.
- Use this tool for debugging and development, not for production monitoring.
- Some checks may be blocked by firewalls or CORS policies.
- All lookups are performed client-side when possible for privacy.
FAQ
What are HTTP response headers?
HTTP headers are metadata sent by servers with responses, containing information about caching, security, content type, and more. This is designed to handle both simple and complex use cases efficiently, giving professional developers a reliable everyday tool.
How do I check headers for a site that blocks CORS?
Use the relay mode (when available) or check from a server environment where CORS restrictions don't apply.
What security headers should I enable?
Essential security headers include HSTS, CSP, X-Frame-Options, X-Content-Type-Options, and Referrer-Policy. This is designed to handle both simple and complex use cases efficiently, giving professional developers a reliable everyday tool.
How can I test CORS and preflight?
The tool analyzes CORS headers and shows whether simple requests, credentialed requests, and preflight requests would be allowed.
What's the difference between HTTP/1.1, HTTP/2, and HTTP/3?
HTTP/1.1 is the traditional version, HTTP/2 adds multiplexing and compression, HTTP/3 uses QUIC protocol for better performance. This is designed to handle both simple and complex use cases efficiently, giving professional developers a reliable everyday tool.
How do redirects affect headers?
Each redirect in the chain can have different headers. The tool shows the complete redirect chain with headers for each hop.