Inspect the HTTP response headers of any URL in real time. Our free HTTP header checker shows the status code, server banner, content type, cache policy, security headers (HSTS, CSP, X-Frame-Options), redirect chain, and cookies — essential for debugging caching, SEO, and security configuration.
Our HTTP Header Checker leverages a globally distributed network of probes, ensuring accurate data from various vantage points, with a strong emphasis on US-based server response insights.
We send a plain HTTP request to the URL you provide and print the complete response head before any HTML is parsed. Every redirect in the chain is shown separately with its own status code and Location target, so a domain that goes apex to www to HTTPS reveals all three hops rather than only the destination.
Status code comes first — 200 is a normal response, 301 is a permanent redirect that passes ranking signals, 302 is temporary and often used by mistake where a 301 belongs. Multiple redirect hops add latency and should be collapsed into one where possible. In the security group, absent is the value to look for: no Strict-Transport-Security means downgrade attacks remain possible, no Content-Security-Policy leaves injected scripts unrestricted, no X-Frame-Options or frame-ancestors directive allows clickjacking.
| Header | Purpose | Recommended value |
|---|---|---|
| Strict-Transport-Security | Force HTTPS | max-age=31536000; includeSubDomains |
| Content-Security-Policy | Block XSS | Strict source allow-lists |
| X-Frame-Options | Prevent clickjacking | DENY or SAMEORIGIN |
| X-Content-Type-Options | Stop MIME sniffing | nosniff |
| Referrer-Policy | Limit referrer leakage | strict-origin-when-cross-origin |
| Permissions-Policy | Restrict APIs | camera=(), microphone=() |
A web administrator uses the redirect checker functionality of the http header checker to identify why an old URL is not redirecting correctly to its new destination, tracing all intermediate 301 or 302 redirects and finding the point of failure.
An SEO specialist performs a security headers check using the tool to confirm that HSTS, CSP, and X-Frame-Options headers are correctly implemented across their client's website, ensuring compliance and preventing common vulnerabilities.
A developer uses the http header checker to inspect Cache-Control and Expires headers, ensuring that static assets are being cached effectively by browsers to improve page load times and reduce server load during peak traffic.
A single-page application developer checks the cors headers with the tool after encountering AJAX request failures, confirming if the Access-Control-Allow-Origin header is correctly configured on the API server to permit requests from their application's domain.
Status code, all response headers, redirect chain, cookies, and a summary of present/missing security headers.
Security headers are specific HTTP response headers designed to enhance website security by mitigating common web vulnerabilities. They are vital because they instruct browsers to enforce certain security policies, preventing attacks like cross-site scripting (XSS), clickjacking, and ensuring secure communication via HTTPS.
At minimum Strict-Transport-Security, Content-Security-Policy, X-Content-Type-Options set to nosniff, a Referrer-Policy, and frame protection via X-Frame-Options or the frame-ancestors directive. Missing ones are the most common findings in a basic security review and most can be added in the server or CDN config without touching application code.
Usually because the apex redirects to www first, then to HTTPS. Configure both at once at the edge to keep it a single 301.
Set the Strict-Transport-Security header at your web server or CDN. Start with a low max-age and raise it once stable.
Yes — free, unlimited, no signup.
An HTTP status code is a three-digit number returned by a web server in response to a browser's request. It indicates the outcome of the request, such as 200 OK (success), 404 Not Found (resource not found), or 500 Internal Server Error (server error).
You can check HTTP status codes using an http status code checker like the one on Site Host Finder. Simply enter a URL, and the tool will display the main status code along with all accompanying response headers, giving you immediate feedback on the request's result.
The HTTP header checker is the fastest way to see exactly what a server tells browsers and crawlers. Use it to debug redirect loops, confirm status codes after a migration, audit security headers and validate caching — then check the SSL certificate and DNS records for the layers underneath.