HTTP headers lookup

About the Free Online HTTP Headers Lookup Tool

Big Free Tools HTTP Headers Lookup can be used by web developers, SEO practitioners and system administrators to see what data, exactly, gets passed from the web server to a client browser when a URL is requested. With a real-time HTTP request made by our tool, you'll see all response headers, status codes and server configurations in real time – no curl command needed.

Primary Groups of HTTP Header Fields Examined

HTTP Status Codes: Determines if the server returned the right code (200 OK), then the page was delivered normally, or, maybe, a redirect was performed, either temporarily 302 or permanently 301. If something was wrong, a code 404 or 403 may be returned, for example.

Security Headers: Audit web protection policies such as Strict-Transport-Security (HSTS), Content-Security-Policy (CSP), X-Frame-Options (clickjacking prevention), and X-Content-Type-Options ( MIME-sniffing prevention).

Discloses what web server software the website uses (for example, Lite Speed, Nginx, Apache, Cloudflare edge proxies, etc.); as well as what backend framework (if any) is utilized.

Caching & Performance directives: Checks the following headers: Cache-Controlexpires, ETag and Vary to test how browsers and CDNs cache your static assets and web pages.

Cookies & Set-Cookie: Assesses the Security attributes of the cookies like Http Only, Secure, and Same Site to make sure application session security.

Why Use an HTTP Header Checker?

Check that the migration of URLs results in a 301 Moved Permanently permanent redirect, instead of a 302 Found temporary redirect, in order to not lose link equity.

Straight away see the cause of the page jumping between multiple redirects or returning a 500 error.

Validate whether your implementation of SSL/TLS actively implements HSTS and secure response policies.