Host.io
Domains data API for developers retrieving internet domain information.
Read docs Updated 2026-06-16
What is Host.io?
Host.io is a domains data API that supplies information about registered internet domains to client applications.
It is useful for developers building tools that require domain lookup, ownership details, or related DNS data.
What you can build with Host.io
Domain intelligence dashboards
Developers fetch WHOIS, DNS, and hosting history for thousands of domains to build internal tools that track infrastructure changes or competitor sites.
Security and threat research
Security teams query the API to map domain ownership, name-server patterns, and historical IP data when investigating phishing or malware campaigns.
Bulk domain monitoring services
SaaS products use Host.io to periodically check registration details, expiration dates, and name-server updates for customer portfolios.
Get started with Host.io
- 1Sign up at host.io and generate an API key
- 2Review the endpoint reference in the documentation
- 3Add the API key to the X-API-KEY header
- 4Make a test HTTPS request to /api/{domain}
- 5Handle JSON responses and respect rate limits
Host.io: pros & cons
Pros
- +Simple API-key authentication
- +All traffic encrypted over HTTPS
- +Focused domain dataset in one place
- +Straightforward integration for scripts
Cons
- –Requires paid plan for high volume
- –No real-time streaming or webhooks
- –Data coverage varies by TLD
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Frequently asked questions
Host.io is an API that returns structured data about internet domains including ownership, DNS, and hosting records.
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