SSL Certificate Checker

Check a domain's SSL/TLS certificate — subject, issuer, validity dates, protocol version, and cipher suite. Useful for verifying a certificate before it expires or diagnosing a TLS issue.

Domain

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Why use SSL Certificate Checker?

This tool connects directly to a domain's server and performs a TLS handshake to retrieve its live certificate, then reports the subject, issuer, validity window, days remaining, protocol version, cipher suite, and Subject Alternative Names — the same information a browser checks when establishing a secure connection.

Key benefits

Connects live to the domain's server for real-time certificate data
Shows days remaining until expiration
Lists all Subject Alternative Names on the certificate

Features

Live TLS handshake to retrieve the certificate
Certificate validity and trust status
Protocol version and cipher suite reporting

Popular use cases

Checking how many days remain before a certificate expires
Verifying a newly issued certificate is correctly installed
Diagnosing a TLS trust or configuration issue

How to use SSL Certificate Checker

1
Enter a domain
Type the domain you want to check (no need to include https://).
2
Check the certificate
Click Check Certificate to connect and retrieve the live TLS certificate.
3
Review the details
See the subject, issuer, validity dates, protocol, and cipher used.

Frequently asked questions

How is this different from viewing the certificate in my browser?

It performs the same kind of check server-side, giving you the same information (subject, issuer, validity, SANs) without needing to open developer tools in your browser.

Why does it say the certificate isn't trusted?

This can happen with self-signed certificates, expired certificates, or a certificate chain that's missing an intermediate — the tool reports the specific authorization error when this happens.

Does checking a certificate affect the target server?

No — this performs a standard TLS handshake, the same connection any browser makes when visiting the site.

Last reviewed: July 2026

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