SSL Certificate Checker
Use our fast SSL certificate checker to diagnose SSL/TLS certificate issues. Verify whether your certificate is correctly installed, trusted, and valid across browsers. Get instant insights into certificate validity, expiration dates, and chain configuration.
SSL Commands Reference
Use these commands to check SSL certificates from your terminal. Click "Copy" to copy any command.
Generate Private Key
openssl genrsa -out private.key 2048
Generate Certificate Signing Request (CSR)
openssl req -new -key private.key -out request.csr
View Certificate Details
openssl x509 -in certificate.crt -text -noout
Check SSL Certificate Remotely
openssl s_client -connect example.com:443 -showcerts
Verify Certificate Chain
openssl verify -CAfile ca.crt certificate.crt
Check Certificate Expiry Date
openssl x509 -in certificate.crt -noout -dates
Convert PEM to PKCS12
openssl pkcs12 -export -in certificate.crt -inkey private.key -out certificate.p12
About SSL/TLS Certificates
What is SSL/TLS?
SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are cryptographic protocols designed to provide secure communication over the internet. They encrypt data transmitted between a user's browser and a web server, protecting sensitive information like passwords, credit card numbers, and personal data.
Why SSL is Important
- Data Encryption: Protects data from interception and eavesdropping
- Trust & Authentication: Verifies that the website belongs to the organization it claims to be
- SEO Benefits: Google prioritizes HTTPS websites in search rankings
- Browser Trust: Users see the padlock icon and green "Secure" indicator
- Compliance: Required for PCI DSS, HIPAA, GDPR, and other regulations
- Prevent Man-in-the-Middle Attacks: Ensures data integrity and authenticity
Types of SSL Certificates
Domain Validation (DV): Basic validation, quick to issue, suitable for blogs and personal websites.
Organization Validation (OV): Verifies organization identity, better for business websites.
Extended Validation (EV): Highest trust level with full verification, shows company name in address bar.
Wildcard Certificates: Secures a domain and all subdomains (e.g., *.example.com).
Multi-Domain (SAN): Secures multiple domains with one certificate.
Certificate Validity and Expiration
SSL certificates typically have a validity period of 1 or 2 years. After expiration, browsers will show security warnings. It's crucial to monitor expiration dates and renew certificates before they expire to avoid service interruptions and user trust issues.
Certificate Chain
A certificate chain consists of three parts: your domain's certificate, one or more intermediate certificates, and the root certificate. All must be properly installed and trusted for HTTPS to work correctly. A broken chain can cause browser warnings and security vulnerabilities.
Common SSL/TLS Issues
- Expired Certificates: Browser shows "Certificate Expired" warning
- Mismatched Domain: Certificate common name doesn't match domain
- Untrusted CA: Certificate issuer not trusted by browsers
- Self-Signed Certificates: Not recognized by browsers, causes warnings
- Incomplete Chain: Missing intermediate certificates in the chain
- Weak Algorithms: Using outdated encryption methods
How Our SSL Checker Works
Our tool connects to your domain, downloads the SSL certificate, and analyzes it to provide you with comprehensive information about its validity, issuance, expiration, and security details. The analysis includes checking certificate dates, issuer information, Subject Alternative Names (SANs), and certificate chain configuration.