What this tool does
Fetches a public site’s TLS certificate and reports the issuer, validity dates, and covered domains. Useful for expiry checks and confirming an installation.
How to use it
- Enter the address with https://.
- Run it to see the certificate details.
- Check that the expiry date and the covered domain list match the hosts you actually serve.
Worked example
Entering https://example.com connects to that host on port 443 and reads the certificate.
Frequently asked questions
- What about addresses that redirect?
- Redirects are reported, not followed. To inspect the final destination’s certificate, enter the redirected address and run it again.
- Can it check an internal server?
- No. It checks hosts reachable from one server on the public internet. Private network addresses will not connect.
What this tool does not cover
It queries from a single location, so it is not a regional availability test. The address you enter is sent to the target server. It does not fully evaluate chain trust or revocation status.