Free SSL Certificate Checker & Trust Diagnostics
Validate certificate expiration dates, intermediate CA trust chains, TLS 1.3 protocol support, and HSTS security posture with instant cryptographic grading.
A+
github.com
Status: Exceptional Security • Protocol: TLSv1.3
Certificate Subject & Validity
Issued identity and operational active windowgithub.com
Sectigo Limited
(Sectigo Public Server Authentication CA DV E36)Sep 1, 2026
Nov 29, 2026
Modern Transport Security Controls
Strict transport enforcement and DNS certificate authority authorizationHTTP Strict Transport Security (HSTS)
DNS CAA Records
PulseDesk Pro • Digital Asset Guardian
Never Let an SSL Certificate or Domain Silently Expire Again
One-time manual checks only test what is happening right now. PulseDesk Pro connects to all your production domains, SSL certificates, cloud hosting, and API secrets 24/7 with automated multi-channel escalation (Email, Slack, Webhook) 30, 14, and 7 days prior to expiry.
Monitor github.com
Track up to 25 websites, SSL certs, cloud clusters, and team licenses in one unified operations desk.Track github.com 24/7Knowledge Base & SEO Guide
Understanding SSL/TLS Certificates & Best Practices
Everything you need to know about SSL validation, certificate chains of trust, modern cipher security, and mitigating costly website downtime.
Google officially confirmed HTTPS as a core ranking signal. When an SSL certificate expires, Googlebot encounters a certificate validation failure and can de-index or drop your search ranking positions. Crucially, desktop and mobile browsers immediately block user traffic with aggressive full-page warnings ("Your connection is not private"), resulting in an immediate 95%+ bounce rate and permanent brand erosion.
Industry security standards set by the CA/Browser Forum drastically reduced certificate lifetimes (from 3+ years down to 398 days, and Let’s Encrypt enforces 90 days; Apple and Google propose 45-day lifetimes). Shorter certificate lifespans limit the window of exposure if a private key is compromised, but they require automated 24/7 monitoring to prevent accidental downtime.
This error occurs when your web server only sends the leaf (server) certificate without bundling the intermediate Certificate Authority (CA) certificates. While some desktop browsers cache intermediate certificates, mobile devices and automated API clients will fail the handshake. To fix this, configure your web server (Nginx, Apache, Caddy, Cloudflare) with the fullchain.pem / bundled certificate bundle.
TLS 1.3 is the newest cryptographic standard. It simplifies the TLS handshake from two round-trips to just one round-trip (1-RTT) and supports Zero Round-Trip Time (0-RTT) for resuming sessions, significantly accelerating mobile page loads. Furthermore, TLS 1.3 eliminates obsolete, vulnerable ciphers (RC4, DES, 3DES, MD5, SHA-1, CBC modes) and requires Perfect Forward Secrecy (PFS) by default.
HSTS is a security response header (Strict-Transport-Security: max-age=31536000; includeSubDomains; preload) that forces all compliant web browsers to communicate exclusively over HTTPS, automatically upgrading any insecure http:// requests before they leave the browser. It completely neutralizes SSL stripping and downgrade attacks.
DNS CAA records allow a domain owner to specify which Certificate Authorities are authorized to issue certificates for that domain. If an unauthorized CA is requested to issue a certificate for your domain, it is required by industry standards to reject the request, defending your business against fraudulent certificate issuance.