Development — entry 039 of 98
Host.io
Host.io indexes WHOIS, DNS, IP, backlink, and technology-fingerprint metadata for the world's registered domains and exposes it through a searchable, filterable REST API - useful for domain research, lead generation, or competitive tech-stack lookups. Every call requires an API key (confirmed live: an unauthenticated request returns a 400 "API Access Token Required"); the free tier allows 1,000 requests a month capped at 5 results per page, with paid plans starting at $99/month for higher volume and deeper pagination.
GreatAPIs Score
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<a href="https://greatapis.com/api/host-io/"><img src="https://greatapis.com/badge/host-io.svg" alt="Scored 75 on greatapis.com"></a>Auth quickstart
- Get a key at the provider
- Send it on every request as a header
Authorization: <key> - The exact header isn't documented — Authorization is a common default; confirm in the provider's docs.
Your key is stored only in this browser (localStorage) and sent directly to the API — never to greatapis.
Developer reference
Free: 1,000 requests/month; Basic: 10,000/month ($10 per extra 1,000); Business: 100,000/month ($10 per extra 1,000); Enterprise: 500,000+/month