SSL Certificate Checker

A quick SSL certificate checker for domain owners and admins to verify expiry, issuer, and chain status without manual certificate inspection.

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Total Calculations Run

< 15ms

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100%

Client-Side Privacy

4.9 / 5.0

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About This Tool

The tool analyzes an SSL certificate for a given domain by performing a TLS handshake and extracting the certificate chain. It surfaces essential details such as expiry date, issuer, subject, and SANs.
Conceptually, it compares the NotBefore/NotAfter validity window to the current time, computes days remaining, and classifies the certificate as valid, expired, or expiring soon. It also reports chain completeness and supported TLS versions or cipher hints.
Who benefits: website owners, IT admins, hosting providers, and SEO analysts who need proactive renewal planning and to avoid HTTPS warnings. Unique value: real-time, no setup required, concise, standardized outputs suitable for automation and monitoring.
Core features include domain input, immediate certificate fetch, expiry and issuer details, SANs, chain status, and optional protocol information. Use cases include verifying a domain after transfer, during renewal, or before a migration, and integrating results into monitoring workflows.

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How to Use

Provide inputs: enter the domain name (and optional port).
The tool connects to the domain on port 443 and retrieves the SSL certificate.
The tool analyzes expiry, issuer, SANs, and chain status.
Review outputs: status, expires, days_remaining, issuer, san_list, and chain_status.
If expiring soon, plan renewal before expiry.

Frequently Asked Questions

Find Quick Answers

What data is shown by the checker?

It displays expiry date, days remaining, issuer, subject, SANs, chain status, and basic protocol information. Outputs are designed for quick risk assessment and integration into monitoring systems.

How is expiry calculated?

Expiry is calculated from the certificate's NotAfter date using current UTC time. Days remaining = ceil((NotAfter - now)/86400). Expired if NotAfter is in the past.

What if the domain has no TLS on port 443?

The checker returns an unknown or error status with a machine-readable reason indicating that TLS could not be established for port 443.

Does this tool perform revocation checks?

No, it does not perform OCSP/CRL revocation checks by default. It focuses on certificate validity, chain completeness, and basic TLS parameters.

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