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CertMonitor: Usage Overview

Why CertMonitor Exists

CertMonitor was born out of real-world frustration: outages and security incidents caused by expired certificates, missing Subject Alternative Names, or incomplete certificate chains. Like many engineers, I was tired of late-night alerts, broken integrations, and the endless scramble to track down certificate issues before they caused downtime or compliance failures.

I created CertMonitor to solve these pain points with a tool that is:

  • Zero-dependency: 100% native Python. No third-party Python packages required—ever. Advanced public key parsing and elliptic curve support are powered by Rust for speed and safety.
  • Portable and secure: Works out-of-the-box in any Python 3.8+ environment, with a minimal attack surface.
  • Extensible: Add your own validators for organization-specific checks, compliance, or custom certificate logic.
  • Fast and reliable: Designed for high-throughput, concurrent monitoring of many endpoints.

What Makes CertMonitor Different?

  • Zero Dependencies: CertMonitor is dependency-free by design. You can drop it into any environment and it just works. (Advanced public key and elliptic curve features are powered by Rust, but all orchestration and logic are pure Python standard library.)
  • Native Python First: All core features use only the Python standard library. This means maximum compatibility, security, and maintainability.
  • Validator System: Modular, pluggable checks for everything from expiration to hostname validation, key strength, protocol version, and more.
  • Labor of Love: This is a passion project, not a commercial product. While we strive for production quality, CertMonitor is always improving—and your feedback and contributions are welcome!

Example: Catching the Issues That Matter

from certmonitor import CertMonitor

with CertMonitor("example.com") as monitor:
    print(monitor.validate())

CertMonitor will check for expiration, hostname mismatches, missing SANs, weak keys, outdated protocols, and more—right out of the box.

Note: CertMonitor is designed to be zero-dependency and portable. Advanced public key parsing and elliptic curve support are powered by Rust, but you never need to install third-party Python packages for orchestration or logic.