Site Reliability Commercial BOFU

How to monitor SSL certificate expiration site-wide

Set up multi-domain SSL expiration alerts at 30, 14, 7, and 1 days, plus cipher and chain validation.

Split padlock with green valid SSL state and red cracked certificate expiration warning
SSL monitoring visual for certificate expiration, chain validity, and renewal alerts.

An expired SSL certificate is one of the few SEO disasters worse than a misconfigured robots.txt. Chrome blocks the page with a full-screen warning. Search Console flags it as a security issue. Organic traffic vanishes for as long as it takes ops to renew — typically a business day, sometimes longer when auto-renewal silently fails.

Step 1. Add every subdomain to SSL monitoring

Site → SSL is on by default in every 2-UA project. For multi-domain teams, add every subdomain: api., blog., app., status.. Auto-renewal misses non-www subdomains more often than teams expect.

Step 2. Configure alert windows

Default thresholds: 30, 14, 7, and 1 days before expiration. For mission-critical sites, add a 60-day renewal-start reminder routed to your DevOps channel. A 60-day heads-up lets ops handle renewal during normal hours, not at 2 AM after an outage.

Step 3. Monitor more than just expiration

2-UA checks the full TLS posture, not just the expiration date:

  • Certificate chain validity — broken intermediates render as untrusted in some browsers.
  • Mixed-content warnings — HTTP assets on HTTPS pages.
  • Self-signed certs on subdomains — usually staging environments leaking into prod DNS.
  • Weak ciphers — TLS 1.0 and 1.1 still served signal poor security hygiene to Google.

Step 4. Route SSL alerts into your incident workflow

Route alerts to Slack with @here, Telegram, or a PagerDuty webhook. SSL is the rare SEO check that is also an uptime check. Treat it as a tier-1 incident signal.

Three classes of silent SSL failures

  • Let's Encrypt auto-renewal failure — silent until 7 days before expiry; usually caused by changed permissions on the ACME challenge directory.
  • Wildcard cert not covering new subdomain*.example.com does not cover *.sub.example.com.
  • CDN cert valid, origin cert expired — both must be valid; checking only the public URL misses the origin.

HTTPS as a baseline, not an advantage

HTTPS has stopped being a ranking advantage; the penalty for not having it dwarfs any uplift. The risk profile is asymmetric — perfect TLS earns nothing, broken TLS costs everything. Continuous monitoring is therefore not optional; it is the floor of acceptable infrastructure hygiene for an SEO-dependent business.

Add your domain to a free 2-UA project for combined SSL, domain, and certificate-chain monitoring across every subdomain you own.