SSL Certificate CheckerTLS Certificate Inspection

Inspect SSL/TLS certificates for expiry dates, issuers, subject alternative names, and configuration issues. Download renewal reminders.

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SSL/TLS Certificate Analysis

SSL/TLS certificates enable encrypted HTTPS connections between browsers and web servers. Our tool connects to your domain over HTTPS and retrieves certificate metadata including issuer, expiry date, subject alternative names, and configuration warnings.

Certificate Issuers and Trust

Certificate Authorities (CAs) issue SSL certificates after validating domain ownership. Common issuers include Let's Encrypt (free, automated, 90-day validity), DigiCert, Sectigo, and GlobalSign (paid, longer validity, additional validation levels).

Browsers trust certificates signed by recognized CAs. Self-signed certificates trigger browser warnings and should only be used for internal testing, never production websites. Let's Encrypt is widely used for production due to automation via ACME protocol.

Subject Alternative Names (SANs)

SANs allow a single certificate to cover multiple domains and subdomains. For example, one certificate might include example.com, www.example.com, api.example.com, and *.example.com (wildcard). This simplifies certificate management compared to issuing separate certificates for each subdomain.

Our tool displays all SANs configured in your certificate. Ensure all domains users access are included in SANs to prevent browser warnings about certificate mismatch.

Certificate Expiry Management

Let's Encrypt certificates expire after 90 days, requiring automated renewal. Commercial certificates last 1-2 years. Expired certificates cause browser errors and prevent users from accessing your site—a common cause of unexpected downtime.

Monitor certificates monthly and set renewal reminders 30 days before expiry. Our tool displays days until expiry and provides downloadable calendar reminders (.ics files) that integrate with Outlook, Google Calendar, and Apple Calendar.

Implement automated certificate renewal using ACME clients like Certbot, acme.sh, or cloud provider integrations. Manual renewal processes are error-prone and lead to forgotten expirations.