SSL Checker
Error
Valid Certificate Invalid / Expired
Subject (Owner) Details
| Common Name (CN) | |
| Organization (O) | |
| Organizational Unit (OU) |
Issuer (CA) Details
| Common Name (CN) | |
| Organization (O) | |
| Organizational Unit (OU) |
Certificate Validity
| Valid From | |
| Valid To | |
| Serial Number |
Properties & Constraints
| Basic Constraints | |
| Key Usage | |
| Extended Key Usage |
Subject Alternative Names (SANs)
Verify your website’s SSL security with a quick and reliable certificate check. Instantly inspect your SSL certificate status, validity, expiration date, certificate chain, and issuing authority. Identify configuration issues or potential trust problems before they affect visitors, helping ensure your website maintains a secure, encrypted connection and protects sensitive information.
Stay ahead of SSL certificate expiration and avoid unexpected security warnings. Monitor certificate validity, expiry dates, and renewal schedules to ensure your website remains trusted and accessible. Proactive SSL monitoring helps prevent expired certificates, browser warnings, connection errors, and potential loss of visitor confidence caused by avoidable security issues.
Verify your SSL certificate’s cryptographic configuration to ensure strong security and compatibility. Review supported signature algorithms, key sizes, encryption parameters, and Subject Alternative Name (SAN) entries. Checking these details helps identify outdated or weak configurations, confirm that domains are correctly covered, and maintain a secure, trusted connection for website visitors.
SSL Certificate FAQS
What is an SSL certificate
An SSL (Secure Sockets Layer) certificate is a digital certificate that verifies a website’s identity and enables an encrypted connection between the web server and a visitor’s browser. It helps protect sensitive information, such as passwords, payment details, and personal data, from being intercepted or tampered with during transmission..
Why is it important to check my SSL status
Regularly checking your SSL status helps confirm that your certificate is valid, correctly configured, trusted, and matches your domain. Monitoring expiration dates can prevent unexpected security warnings, connection errors, and browser alerts. Maintaining a valid SSL certificate protects visitor data, supports website security, and helps preserve user trust and credibility.
How do I fix a "Domain Mismatch" error
A “Domain Mismatch” error occurs when the website’s domain is not included in the SSL certificate’s Common Name (CN) or Subject Alternative Names (SANs). To fix it, obtain or reissue a certificate that correctly includes the required domain names. Then install the updated certificate and verify the configuration.
What does the Signature Algorithm mean
The Signature Algorithm specifies the cryptographic method a Certificate Authority (CA) uses to sign an SSL certificate and verify its authenticity. It combines a hashing function with a digital signature method. Modern certificates commonly use SHA-256 with RSA or ECDSA, providing strong security and helping prevent certificate tampering or forgery.
What are Subject Alternative Names (SANs)?
SANs are an extension in SSL certificates that allow you to secure multiple domain names, subdomains, or IP addresses under a single certificate instead of purchasing separate ones.
How often do SSL certificates need renewal?
Most commercial SSL certificates are valid for 1 year, while free certificates (like Let's Encrypt) are valid for 90 days. It is highly recommended to set up auto-renewal to prevent service disruption.