Developer
SSL Cert Checker
Check SSL certificate validity and details for any domain. Uses SSL Labs / crt.sh data.
How SSL/TLS Works
TLS Handshake: Client → Server Hello → Certificate → Key Exchange → Encrypted connection
Certificate Chain: Root CA → Intermediate CA → Domain Certificate
Common Issuers: Let's Encrypt (free), DigiCert, Sectigo, GlobalSign
Validity: Max 398 days (since 2020 browser policy)
Certificate Types
${[['DV (Domain Validated)','Basic — just proves domain ownership'],['OV (Org Validated)','Org identity verified by CA'],['EV (Extended Validation)','Highest trust — full company verification'],['Wildcard (*.domain.com)','Covers all subdomains'],['SAN / Multi-domain','Multiple domains in one cert'],['Self-Signed','No CA trust — dev/internal use']].map(([t,d])=>f'
').join('')}