How AxelBase SSL Checker Works Under the Hood

Published: November 13, 2025 • 5 min read

You enter a domain. Two seconds later, you see the certificate details. No server. No tracking. Here’s how it actually works.

Step 1: Smart Domain Extraction

Whether you paste github.com, https://github.com, or https://github.com/explore — the JavaScript URL API cleanly extracts just the hostname.

Step 2: Bypassing CORS with a Public Proxy

Direct browser requests to most SSL APIs are blocked by CORS. We route through a trusted public proxy (api.codetabs.com) that adds the required headers.

Step 3: Calling the Real API

The actual data comes from ssl-checker.io — a fast, reliable public API that returns issuer, validity dates, and days remaining.

Step 4: Parsing & Color Logic

Once JSON arrives, we extract:

• issuer_cn → human-readable issuer
• valid_from / valid_till → dates
• days_left → badge color

Privacy by Design

No cookies. No localStorage. No analytics. Your input never leaves your browser except via the proxy — and even that is anonymized.

100% client-side. 0% data collection.

This tool proves you don’t need a backend to build powerful, privacy-respecting web apps.

Open source • MIT licensed • Built with SvelteKit