Development — entry 039 of 100
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.
AuthenticationAPI KeySign up with the provider to obtain credentials.
HTTPSSupportedTraffic is encrypted in transit.
CORSEnabledCallable directly from browser JavaScript.
PricingFreemiumA usable free tier exists, with paid plans for more volume.
FormatsJSONResponses can be requested as JSON.
GreatAPIs Score
Score75
Authentication15/25API key required
Pricing17/20Freemium tier available
Docs14/20Documentation URL provided
Formats9/15Single response format
Freshness20/20Verified within 6 months
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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
- Sign up with the provider to get an API key.
- 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.
Stored keyNo key stored
Your key is stored only in this browser (localStorage) and sent directly to the API — never to greatapis.