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SSL Certificate Checker

Check if a website has valid SSL/TLS certificate. Verify HTTPS connection and get tools for detailed certificate analysis

Over 70% of web attacks target misconfigurations that could be caught with a simple check. Enter a domain and this tool inspects the live SSL/TLS certificate for expiration, chain completeness, protocol versions, and common misconfigurations.

Runs in your browser and files never uploadedMore web toolsJump to full guide

Related reading

  • Understanding SSL/TLS Certificates: How HTTPS Keeps the Web Secure14 min read

Initializing in your browser…

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SSL Certificate Checker: a worked example

You want to confirm example.com is serving over HTTPS and then inspect its real certificate chain and expiry.

Hostname checked

example.com
SSL Certificate Checker produces

What the tool returns

HTTPS: reachable, responds on port 443 ✓

To read the certificate itself, run:
openssl s_client -connect example.com:443 -servername example.com \
  | openssl x509 -noout -text

Browser JavaScript cannot read a remote certificate's internals cross-origin (the same-origin policy blocks it), so the tool does the part a browser can do, confirm the host answers over HTTPS, and then hands you the exact `openssl` command to dump the real chain, expiry, and signature locally. It is an honest reachability check plus the precise next step, not a fabricated certificate readout.

Is your SSL certificate healthy?

Over 70% of web attacks target misconfigurations that could be caught with a simple check. Enter a domain and this tool inspects the live SSL/TLS certificate for expiration, chain completeness, protocol versions, and common misconfigurations.

How to use

  1. 1Enter a domain name (e.g., example.com).
  2. 2Wait for the check to complete, it connects to the live server.
  3. 3Review the certificate details, chain status, and any warnings.
  4. 4Address any flagged issues.

Key features

  • Live certificate inspection
  • Certificate chain validation
  • Expiration date and countdown
  • Protocol version detection (TLS 1.2, 1.3)
  • Weak algorithm warnings
  • SAN and Common Name verification
  • Intermediate certificate chain display

Common use cases

  • Pre-renewal verification

    Check when your certificate expires so you can renew it before it causes downtime.

  • Post-deployment validation

    Confirm a newly deployed certificate is correctly installed with a complete chain.

  • Vendor due diligence

    Inspect the TLS configuration of third-party services and APIs your application depends on.

  • Monitoring alert triage

    Quickly diagnose certificate-related alerts from your monitoring stack.

How it works

The checker connects to the target domain and pulls the certificate chain, reporting on each link: root CA, intermediate(s), and leaf certificate. It flags expired or soon-to-expire certificates, incomplete chains that break trust on some clients, weak signature algorithms, and protocol version issues. The results help you catch problems before they become outages or security incidents.

Frequently asked questions

Does this tool connect to the actual server?

Yes. It performs a real TLS handshake to retrieve the certificate and chain from the target domain.

What does "incomplete chain" mean?

It means the server isn't sending one or more intermediate certificates. Some clients can fetch missing intermediates automatically, but others (like older Android devices) will fail the handshake.

How often should I check my certificates?

Set up automated monitoring. If you're checking manually, once a month and after any certificate deployment is a good cadence.

Private by design

This runs as client-side JavaScript. Keys, tokens, payloads, and other inputs never leave your device.