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Kordu Tools

SSL Certificate Checker

Check SSL/TLS certificate details for any domain using Certificate Transparency logs.

How to use

  1. 1

    Enter a domain

    Type the domain you want to check, such as example.com.

  2. 2

    Run the check

    Click the Check SSL button or press Enter to query Certificate Transparency logs.

  3. 3

    Review certificate details

    See the issuer, validity dates, days remaining, and status badge (valid, expiring, or expired).

  4. 4

    Check SANs

    Review the Subject Alternative Names to see all hostnames covered by the certificate.

Frequently asked questions

Where does the certificate data come from?
Data is sourced from Certificate Transparency (CT) logs via crt.sh. CT logs are a public, append-only record of all publicly trusted certificates issued by certificate authorities.
Why might the certificate shown differ from my browser's?
CT logs record all issued certificates, including older or duplicate ones. The tool shows the most recently issued valid certificate, which may differ from the specific leaf certificate your browser negotiates during a TLS handshake.
What does Expiring Soon mean?
Certificates with fewer than 30 days remaining before expiry are flagged as Expiring Soon with an amber badge. This gives you time to renew before the certificate expires.
Is this tool private?
The only external request is to crt.sh, which queries public Certificate Transparency logs. No personal data is sent or stored.

Inspect the SSL/TLS certificate for any domain. This tool queries

Certificate Transparency logs via crt.sh to find the most recently

issued valid certificate and displays key details: subject common name,

issuer (e.g. Let's Encrypt, DigiCert), validity dates, days remaining

until expiry, serial number, and all Subject Alternative Names (SANs).

Certificates are colour-coded by status — green for valid, amber for

expiring within 30 days, red for expired. Use it to monitor certificate

health, verify issuers, or discover all hostnames covered by a

certificate. All lookups run in your browser.

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