About the SSL Checker

SSL Checker is a free online tool that inspects the SSL/TLS certificate of any public domain — showing expiry date, issuer, subject alternative names, key size, and days until renewal is needed.

How It Works

You enter a domain name (e.g., example.com). Our server opens a TLS connection to port 443 of that domain using Node.js's built-in tls module, retrieves the peer certificate, and closes the connection. The certificate's fields are parsed:

• Subject CN (common name)
• Issuer organisation and CN
• Valid from / valid to dates
• Days until expiry (or days since expiry if already expired)
• Subject Alternative Names (SANs) — the domains the certificate is valid for
• Key size in bits
• Serial number

What Is sortout.app?

sortout.app is a growing collection of focused web tools, each designed to do exactly one thing well. Every tool is free, requires no account, and is built to load fast anywhere.

Privacy

The domain name you enter is sent to our server over HTTPS. Our server then connects to that domain on port 443 to retrieve its certificate. No data about the connection is stored. See our full Privacy Policy.

Frequently Asked Questions

Is this tool free?

Yes, completely free with no usage limits.

Do I need to create an account?

No. There is no sign-up, no login, and no registration of any kind.

Why does it say "certificate not found"?

The domain may not have SSL enabled, may be blocking external connections on port 443, or may not exist.

Can I check subdomains?

Yes — enter the full subdomain (e.g., mail.example.com). The tool connects to that specific hostname and retrieves its certificate.

How many days before expiry should I renew?

Most certificate authorities recommend renewing at least 30 days before expiry. Let's Encrypt automatically renews 30 days before. Treat anything under 30 days as urgent.

Contact

Questions or feedback? Open an issue at github.com/sortout-app/feedback or email hello@sortout.app.