SSL Certificate Checker
Check TLS issuer, expiry and covered domains.
Use the SSL Certificate Checker tool
What this ssl certificate checker does
SSL Certificate Checker searches public Certificate Transparency (CT) logs via Cert Spotter for certificates issued to a hostname and shows the issuer, validity window, days remaining, revocation status, SHA-256 fingerprint and the names the certificate covers. It is the quickest way to confirm that a renewal was actually issued and to see whether www and the apex domain share one certificate.
If the KitJade API is configured, the tool also makes a live HTTPS request to confirm the host answers. CT logs record certificates that were issued and publicly logged — they cannot prove which certificate a particular server serves at this instant, so treat the result as strong evidence rather than a handshake transcript. Dedicated TLS clients such as openssl s_client show the exact chain a server returns.
Why use it
- Confirm that certificate renewal actually deployed before an expiry deadline.
- Find out whether www and the apex domain are both covered by the same certificate.
- Check a vendor's certificate expiry during a security review.
How to use it
- 1Enter a hostname such as example.com — no path and no https:// prefix.
- 2Run the check to search Certificate Transparency logs for that name.
- 3Review issuer, validity window, remaining days and subject alternative names.
- 4Set a renewal reminder if fewer than 30 days remain.
Worked examples
Healthy certificate
Input
example.com
Output
Issuer: public CA · Valid: 90-day window · Days remaining: 62 · SANs: example.com, www.example.com
Exact values depend on what is present in Certificate Transparency logs when you run the check.
Renewal risk
Input
A host with 12 days remaining
Output
Warning · expires in 12 days · check that automated renewal is working
Common mistakes
- Checking only the apex domain when visitors use www — they can have different certificates.
- Assuming a valid certificate means the site is trustworthy; certificate issuance does not vet business honesty.
- Waiting until the expiry day to renew. Certificate authorities and clients have different clocks and caches.