Free tool
DNS & lookupSSL Certificate Checker
Read the live TLS certificate for a public hostname: subject, issuer, SANs, fingerprints, and validity window.
Looks up public internet data for the target you enter. We do not store results.
Free toolBrowser padlocks hide the details cybersecurity students and website owners need when something goes wrong. This free SSL certificate checker opens a TLS session to a public host and shows common name, issuer, subject alternative names, fingerprints, and dates so you can troubleshoot web security and email-related TLS endpoints with evidence. Small businesses can confirm a new certificate actually matches the hostname customers type.
How to use the SSL Certificate Checker
- 1
Enter a public hostname such as www.example.com (no path required).
- 2
Tap Check certificate to open TLS on port 443 from our servers.
- 3
Review CN, issuer, SANs, validity dates, trust note, and fingerprints.
Why reading certificates beats guessing
Name mismatches, wrong intermediates, and expired leaves produce different browser errors. Security testing that only says “HTTPS failed” wastes time. IT and cybersecurity students who inspect SANs and issuer fields diagnose hostname, chain, and renewal issues faster—skills that transfer to email security gateways that also present certificates.
Certificate inspection example
Check example.com. You should see a publicly trusted leaf certificate, one or more DNS SANs covering the hostname, and a future expiry date. Compare the fingerprint after a renewal to confirm the change actually deployed.
Guides and next steps
Privacy note
We open a short TLS connection to the public host you enter and return certificate metadata. We do not store certificates or hostnames.
Frequently asked questions
Explore more
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