HTTP Header Checker
See a page's full response headers — server, caching, security headers and more.
Frequently Asked Questions
Is the HTTP Header Checker really free?
Yes — unlimited use, no signup, no credit card. We built these tools to help you audit sites without paying for a data subscription.
Does this tool store or share the URLs I check?
No. Each check runs live and we don't save your input. We keep a short-lived rate-limit counter (by IP) purely to prevent abuse; it is not linked to your results.
How accurate are the results?
This tool reads live, public data directly from the page or domain you enter — it does not rely on a paid third-party database, so it reflects exactly what is publicly visible right now.
Every time a browser or crawler requests a page, the server responds with HTTP headers — metadata about the response that never appears on the visible page but controls caching, security, content type, compression, and more. Inspecting these headers is essential for diagnosing technical issues and verifying security and performance configuration. This tool shows you a page's full set of response headers.
How to Use This Tool
Enter a URL and click Check Headers. The tool requests the page and displays every response header the server returns.
What This Tool Checks
The HTTP status code and all response headers, including content type, caching directives (Cache-Control, Expires), security headers (Strict-Transport-Security, X-Frame-Options, etc.), server software, and compression indicators.
Understanding Your Results
Caching headers tell you whether and how long browsers and CDNs will cache the page — important for performance. Security headers indicate how well-hardened the site is against common attacks. The server header reveals the underlying web server. A missing Cache-Control on static assets is a common, easily-fixed performance issue.
How to Fix Common Problems
Add missing security headers through your web server config or a security plugin. Configure appropriate cache headers for static assets (long cache times) versus HTML (shorter or validated caching). If content isn't compressing, enable gzip or Brotli compression at the server or CDN level.
SEO Best Practices
Configure the core security headers (HSTS, X-Content-Type-Options, X-Frame-Options, and a Content-Security-Policy where feasible). Set long cache lifetimes on versioned static assets to speed up repeat visits. Use this tool to confirm your CDN or caching plugin is actually applying the headers you expect.
Example
Checking a page reveals no Cache-Control header on its CSS and JS files — adding long-lived cache headers to those static assets noticeably speeds up repeat page loads.
Common Mistakes to Avoid
Don't set aggressive cache headers on your HTML pages if you update content frequently — you'll serve stale content to returning visitors. Don't add an overly strict Content-Security-Policy without testing; it can silently break scripts and styles.
Related SEO Guides
Strong technical setup plus quality backlinks is how pages rank — we handle the links.