SSL / TLS Certificate Checker
Inspect the SSL / TLS certificate for a domain, including issuer, validity period, subject alternative names, OCSP URLs, TLS version, and certificate chain.
Enter a domain name to inspect its SSL / TLS certificate.
Certificate summary
Idle
Domain
Port
Valid
Matched hostnames
Issuer
Subject
Serial number
Signature algorithm
TLS version
Valid from
Valid to
Days left
OCSP URLs
Subject Alternative Names
Certificate chain
Raw JSON
What is an SSL / TLS certificate checker?
An SSL / TLS certificate checker helps you inspect the HTTPS certificate served by a domain.
It is useful for checking expiration dates, issuer details, subject alternative names, supported TLS information, OCSP endpoints, and the certificate chain.
How to use the SSL / TLS Certificate Checker
- Enter a domain name.
- Optionally adjust the port if needed.
- Click Check certificate.
- Review validity, expiration, issuer, SANs, OCSP URLs, and raw JSON details.
Tips
- A certificate may be valid but still expire soon.
- Subject Alternative Names show which hostnames are covered.
- The issuer helps identify which CA issued the certificate.
- Raw JSON is useful for debugging or automation.
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SSL / TLS Certificate Checker FAQ
Can I check certificate expiration?
Yes. The tool shows the valid-to date and the number of days left.
Does it show SANs and issuer?
Yes. The checker includes Subject Alternative Names and issuer information.
Can I inspect the certificate chain?
Yes. The tool includes a simplified certificate chain overview.