HTTP Header Checker
Analyze HTTP headers for security, caching, CORS configuration, and best practices
Raw Headers
Paste HTTP headers and click Analyze
Security Headers, CORS, and Cache Checks
Inspect response headers for any URL and quickly understand security, CORS, caching, redirects, cookies, content type, and CDN behavior. The analyzer highlights important headers like Content-Security-Policy, Strict-Transport-Security, X-Frame-Options, Cache-Control, ETag, and Access-Control-Allow-Origin.
Key Features
- Fetch and inspect HTTP response headers from any public URL
- Security header checks for CSP, HSTS, X-Frame-Options, X-Content-Type-Options, and Referrer-Policy
- CORS header analysis for cross-origin API debugging
- Cache header review for Cache-Control, ETag, Last-Modified, Expires, and Vary
- Cookie flags review for Secure, HttpOnly, and SameSite settings
- Readable explanations that help turn raw headers into clear next steps
- Free online checker with no sign-up required
Common Use Cases
- Auditing a production site before launch
- Debugging CORS errors between a frontend and API
- Checking whether CDN and browser caching are configured correctly
- Reviewing security hardening after a deployment
- Comparing headers across staging and production domains
- Finding redirect, content type, compression, and cookie configuration issues
Frequently Asked Questions
How do I check HTTP headers online?
Enter a URL, run the analyzer, and review the response headers grouped by security, CORS, caching, cookies, and general metadata. The tool explains important headers and flags missing security protections.
Which security headers should a website have?
Most sites should consider Content-Security-Policy, Strict-Transport-Security, X-Frame-Options or frame-ancestors, X-Content-Type-Options, Referrer-Policy, and a restrictive Permissions-Policy.
Can this help debug CORS errors?
Yes. The analyzer shows Access-Control-Allow-Origin, Access-Control-Allow-Methods, Access-Control-Allow-Headers, Access-Control-Allow-Credentials, and related preflight behavior so you can spot mismatches quickly.
Why do cache headers matter?
Cache-Control, ETag, Last-Modified, Expires, and Vary decide how browsers and CDNs reuse responses. Good cache headers can improve speed, while incorrect headers can serve stale content or bypass useful caching.