WhoisJSON – Unified WHOIS, DNS, and SSL API with free tier

Summary: WhoisJSON provides a single API key for WHOIS lookups, DNS records, SSL validation, and domain availability across 1,500+ TLDs with JSON or XML responses. It offers a free plan with 1,000 monthly requests and requires no credit card.

What it does

It delivers WHOIS, DNS, SSL, subdomain discovery, and domain monitoring data via one API key, supporting RDAP and multiple response formats.

Who it's for

Developers and security teams needing affordable, production-ready domain and SSL data access.

Why it matters

It simplifies domain data retrieval by consolidating multiple services into one API with a free usage tier.