Web Diagnostic

Diagnose DNS, HTTP, SSL/TLS, redirects and timing for any website.

Web Diagnostic helps developers investigate website connectivity and server issues directly from Chrome. Open a website, click the Web Diagnostic icon, and press DIAGNOSE to run a diagnostic check. **What it checks** • DNS: Check whether the domain resolves and view DNS lookup timing. • HTTP: Inspect the HTTP status code, protocol, and selected response headers. • Redirects: View redirect steps and identify redirect loops. • SSL/TLS: Examine certificate validity, hostname matching, issuer, and expiration. • Response timing: Review DNS lookup, TCP connection, TLS handshake, and response timing where available. **How it works** Web Diagnostic sends your diagnostic request to its diagnostic server, which checks the website from the server's network perspective. Results may differ from what your browser experiences because the checks run from a different network. The extension does not send a diagnostic request until you press DIAGNOSE. The website address's query string and fragment are excluded from the diagnostic request. No account is required. Results can be copied as JSON for debugging and bug reports. Web Diagnostic is a troubleshooting tool for developers and website administrators. It does not guarantee that a website is available to every visitor or that every reported issue can be detected.