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SSL Monitor

By Cod Xpert
Free Public Diagnostic Tool

Instant SSL Certificate & Expiry Checker

Perform a live port 443 TLS handshake on any domain. Check remaining validity days, Certificate Authority (CA) issuer details, expiration dates, and SAN hostname coverage in real time.

Try quick examples:
SSL Knowledge Base

Why Monitor SSL Certificates Continuously?

A single expired certificate breaks customer checkout, damages SEO rankings, and exposes client data

What is an SSL Problem Detector? ▼
An SSL problem detector verifies that a web server's SSL/TLS certificate is properly configured, cryptographically signed by a trusted root Certificate Authority, matches the accessed domain name, and has not passed its expiration timestamp. Even minor mismatches will cause modern web browsers like Google Chrome and Apple Safari to block visitors with alarming full-screen security warnings.
Why do certificates expire unexpectedly? ▼
Automated certificate authorities like Let's Encrypt issue certificates with a 90-day validity window. If ACME renewal cron jobs fail due to web server restarts, API rate limits, or DNS changes, the certificate will silently expire. Setting up an external monitor like Cod Xpert SSL Monitor ensures your engineering team is notified weeks before any outage occurs.