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SSL/TLS Certificate Deep Inspector

Connects directly to a host and port, walks the full presented certificate chain, and reports the negotiated protocol/cipher, key strength, SAN coverage and expiry, plus a downloadable calendar reminder so a renewal doesn't sneak up on you.

📖 Guide: How to read a certificate chain

Last updated: September 9, 2026

How to use this tool

1. Enter a hostname (and port, if not 443) and click Inspect.
2. Check the negotiated protocol — TLS 1.2 or 1.3 is expected; TLS 1.0/1.1 support is a deprecated-protocol finding worth fixing.
3. Review the certificate chain for completeness; a chain missing an intermediate certificate can pass in some browsers and fail in others.
4. Download the calendar reminder so the certificate's expiry doesn't catch you off guard.

Use it to confirm a new certificate installed correctly, to diagnose "certificate not trusted" errors some visitors report but you can't reproduce, or as a periodic check ahead of renewal.