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SSL Certificate Checker

Network

Inspect SSL/TLS certificates: expiry, issuer, SANs, and fingerprint for any domain

Enter a domain and get back its certificate's issuer, subject, validity dates, fingerprint, and subject alternative names, flagged clearly if the certificate has already expired or is expiring soon, which is worth checking proactively rather than finding out from a production outage. Since browsers can't open a raw TLS socket to an arbitrary port themselves, this genuinely runs server-side: Utilix's backend opens the real TLS connection to the domain and inspects the certificate the server presents, so it's the domain being contacted, not your own machine. It reports on the leaf certificate the server actually serves, including invalid or self-signed ones, rather than performing full trust-chain validation, so a missing intermediate certificate is a separate class of problem a dedicated chain analyzer is better suited to catch.

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How to use SSL Certificate Checker

  • 1.Enter a domain to inspect its live SSL/TLS certificate: issuer, expiry date, and subject alternative names (SANs).
  • 2.Check the expiry date proactively before it lapses and causes browser warnings or API client failures in production.
  • 3.Compare the certificate's SANs against the domains you expect it to cover when debugging a mismatched-certificate error.

Frequently asked questions

Does this check the certificate chain, not just the leaf cert?
It primarily reports on the server's presented leaf certificate details; for full chain validation issues (like a missing intermediate cert), a dedicated SSL chain analyzer gives more depth.
Can I check a certificate on a non-standard port?
This depends on the tool's implementation — if only port 443 is supported, checking a service on a custom port (e.g. a mail server on 465) won't work directly.
Does this tool connect to the domain from my browser or a server?
The TLS handshake to fetch the certificate is performed server-side (browsers can't make raw TLS connections to arbitrary ports), so the domain you enter is contacted by our backend, not your machine.
Will this tell me if the certificate is trusted by browsers?
It shows issuer and validity details, but doesn't run a full trust-store validation across every browser/OS combination — self-signed or privately-issued certs will show their details even though browsers would reject them.

Use via API, SDK, or MCP

cURL# Free: 1,000 req/day · Pro: 10,000 req/day
curl -X POST https://api.utilix.tech/v1/tools/ssl-check \
  -H "Authorization: Bearer utx_live_..." \
  -H "Content-Type: application/json" \
  -d '{"hostname":"example.com","port":443}'

Get an API key from your dashboard · Full API docs →

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