Certificate Monitor

This tool provides multi-domain TLS certificate monitoring for IT operations and security teams, preventing outages caused by expiring or misconfigured certificates. It inventories configured domains, retrieves current certificates via TLS, and reports expiry, issuer, SAN coverage, and chain validity. It supports bulk portfolios and scheduled checks across environments (prod, staging, and test).

Conceptually, the system executes periodic TLS handshakes to fetch certificate data, parses X.509 attributes, and computes days_to_expiry. It classifies health as OK, EXPIRING, EXPIRED, or UNREACHABLE. Results are exposed per domain and can be grouped by environment to simplify renewal planning and risk assessment.

Unique value lies in centralized visibility, automation-ready outputs, and consistent policy compliance. Core features include: domain list ingestion; per-domain expiry date, issuer, subject, SANs, and chain validity; days_to_expiry and status; configurable alert thresholds; and multi-channel notifications. Optional capabilities include CSV/API bulk import/export, historical expiry trends, environment grouping, and integration hooks for ticketing or incident systems. Additionally, support for wildcard and SAN coverage checks, multiple certificates per host, and detection of chain issues enhances robustness.

Typical use cases include proactive renewal planning for large portfolios; pre-renewal checks after certificate issuance; onboarding of new domains; and compliance audits. By surfacing certificate health before expiration, it reduces downtime, improves client trust, and supports audit readiness.