Utility #6Native Node TLS

SSL/TLS Certificate & Expiry Checker

Inspect website SSL validity, expiration date countdown, issuing Certificate Authority (CA), and negotiated TLS protocol ciphers in real time.

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SSL/TLS & OpenSSL CLI Diagnostics Cheat Sheet1-Page PDF

Download our printable quick reference sheet for OpenSSL commands (s_client, x509 expiration, modulus verification), CSR creation, and certificate file formats (.pem, .crt, .key, .pfx).

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Understanding SSL/TLS Certificate Verification

Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protect web traffic from eavesdropping and man-in-the-middle (MITM) attacks. Regular certificate audits ensure zero downtime and strict cryptographic compliance.

1. Trust Chain Hierarchy

Trust flows from a trusted Root CA in the operating system store down through Intermediate CAs to the end-entity leaf certificate presented by the web server.

2. Automated Expiry Tracking

Most modern certificates (such as ACME Let's Encrypt) renew every 90 days. Industry best practice recommends alerting teams when less than 30 days remain.

3. Modern TLS 1.3 Standards

TLS 1.3 improves handshake latency to 1-RTT (or 0-RTT resumption) and removes insecure legacy ciphers (such as RC4, 3DES, and CBC-mode AES).

Frequently Asked Questions About SSL/TLS

Technical answers regarding certificate issuance, validity windows, and security configurations.

Our backend initiates a secure TLS handshake with the requested hostname using native Node.js TLS sockets on port 443 with Server Name Indication (SNI). It extracts the public peer certificate chain, parsing validity dates, issuer information, Common Name (CN), and Subject Alternative Names (SANs) directly from the X.509 structure.