SSL Certificate Checker
Enter a domain to inspect its SSL certificate: issuer, subject, validity dates, expiry countdown, SANs, and cipher suite. Warns about expiring, self-signed, or misconfigured certificates.
Queries crt.sh (Certificate Transparency logs) which can sometimes be slow or rate-limited. For real-time validation, use SSL Labs.
Frequently Asked Questions
What is an SSL certificate?
An SSL/TLS certificate enables HTTPS encryption between a browser and web server, proving the server's identity and encrypting data in transit. Modern certificates are issued by Certificate Authorities (CAs) like Let's Encrypt, DigiCert, and Sectigo.
How often should I renew my SSL certificate?
Let's Encrypt certificates expire every 90 days (auto-renews if configured). Commercial certificates expire every 1-2 years. Set up monitoring alerts at 30 days before expiry. Cloudflare and most CDNs manage SSL automatically.
Why is the check slow or timing out?
This tool queries crt.sh, a public Certificate Transparency log database. It can be slow during high traffic or rate-limited. The tool retries once automatically on timeout. For faster results, try SSL Labs or Qualys SSL Test.