Host.io API for Domain & DNS Intelligence

Overview

Host.io offers an API that provides access to a comprehensive database of domain, IP, and technology data. Established in 2018, the platform is designed for developers and technical buyers who require programmatic access to detailed web infrastructure information. The core products include a Domain API, Reverse IP API, and Domain Search API, each tailored to specific data retrieval needs. The Domain API, for instance, allows users to query specific domain names to retrieve current and historical registration details, nameserver information, and associated IP addresses. This can be critical for verifying domain ownership in fraud prevention workflows or tracking changes in DNS records over time.

The Reverse IP API extends this capability by enabling users to identify all domains hosted on a specific IP address. This functionality is particularly useful for cybersecurity intelligence, where identifying co-located malicious domains can help in threat correlation and infrastructure mapping. For competitive analysis, this API can reveal which of a competitor's domains share hosting infrastructure or might be part of a larger network. The Domain Search API facilitates broader investigative tasks, allowing users to search for domains based on various criteria, such as keywords, TLDs, or specific technological footprints.

Developers often utilize Host.io for tasks such as identifying phishing sites, monitoring brand mentions across new domain registrations, or enriching customer data with technological insights. For example, a market research firm might use the API to identify websites built with a specific content management system (CMS) within a certain industry, providing data points on market penetration and technology adoption. Similarly, domain portfolio managers can automate the tracking of their assets, ensuring records are up-to-date and identifying potential expiration risks. The API supports various programming languages through client libraries, including Python, Go, and Node.js, and provides extensive documentation with interactive examples to assist developers in integration.

Host.io's service includes a free Developer Plan offering 500 credits per month, allowing initial exploration and testing of the API capabilities before committing to a paid plan. This entry-level access enables smaller projects or individual researchers to experiment with domain data querying. For larger-scale operations, paid plans provide higher credit volumes suitable for extensive data collection or real-time monitoring applications. The platform's commitment to compliance, specifically GDPR, addresses data privacy concerns for users operating in regions with strict regulatory frameworks.

Key features

• Domain API: Provides current and historical data for individual domain names, including registration details, nameservers, and linked IP addresses.
• Reverse IP API: Identifies all domains hosted on a given IP address, useful for uncovering interconnected web properties and infrastructure.
• Domain Search API: Allows querying for domains based on keywords, TLDs, technologies detected, or other criteria to support market research and competitive intelligence.
• Technology Detection: Identifies web technologies used by domains, such as CMS, web servers, analytics tools, and programming languages.
• WHOIS Data Access: Offers parsed WHOIS records for domain ownership information, including registrant contact details where publicly available.
• DNS Record History: Provides historical DNS records, showing changes to A, CNAME, MX, and NS records over time.
• Subdomain Enumeration: Lists known subdomains for a given root domain, aiding in comprehensive asset discovery.

Pricing

Host.io offers a tiered pricing structure that includes a free developer tier and scales up to custom enterprise solutions. Pricing is based on credits, with different API calls consuming varying numbers of credits. As of May 2026, the available plans are summarized below.

For detailed pricing information and current offerings, refer to the official Host.io pricing page.

Common integrations

Host.io's API is designed for direct integration into custom applications and analytical platforms. Its utility often extends to:

• Security Information and Event Management (SIEM) Systems: Integrating domain and IP intelligence into SIEMs to enhance threat detection and incident response workflows.
• Threat Intelligence Platforms: Enriching existing threat feeds with additional context about malicious domains and IP infrastructure.
• CRM and Marketing Automation Tools: Augmenting customer profile data with insights into their website's technology stack for targeted marketing or lead qualification.
• Business Intelligence Dashboards: Incorporating domain data for market trend analysis, competitive benchmarking, and industry-specific research.
• Domain Monitoring Tools: Building custom alerts and monitoring solutions for domain portfolio management, brand protection, and compliance.
• Data Orchestration Platforms: Using platforms like Tray.io for workflow automation to connect Host.io data with other business applications.

Alternatives

While Host.io provides extensive domain and DNS intelligence, several other providers offer similar or complementary services:

• WhoisXML API: Offers a comprehensive suite of APIs for WHOIS data, domain intelligence, and IP geolocation, often used for cybersecurity and brand protection.
• BuiltWith: Specializes in website profiler and technology lookup, providing insights into a website's underlying technologies, e-commerce platforms, and analytics tools.
• SecurityTrails: Focuses on cybersecurity data, offering historical DNS, WHOIS, and passive DNS data for threat intelligence and attack surface management.
• URLScan.io: While primarily a sandbox for analyzing suspicious URLs, it also provides detailed technical information about scanned domains, including IP addresses and observed technologies.
• Censys: Offers a search engine for internet-wide scan data, allowing users to discover hosts and networks exposed on the internet, which can be used for security research similar to Host.io's broader domain searches.

Getting started

To begin using the Host.io API, developers typically obtain an API key from their account dashboard. The API uses standard HTTP requests, and responses are returned in JSON format. The following Python example demonstrates how to query the Domain API for information about example.com using the requests library.

import requests
import json

API_KEY = "YOUR_API_KEY"
DOMAIN = "example.com"

url = f"https://api.host.io/domain/{DOMAIN}"
headers = {
    "Host-API-Key": API_KEY
}

try:
    response = requests.get(url, headers=headers)
    response.raise_for_status()  # Raise an HTTPError for bad responses (4xx or 5xx)

    domain_data = response.json()
    print(json.dumps(domain_data, indent=2))

except requests.exceptions.HTTPError as http_err:
    print(f"HTTP error occurred: {http_err}")
except requests.exceptions.ConnectionError as conn_err:
    print(f"Connection error occurred: {conn_err}")
except requests.exceptions.Timeout as timeout_err:
    print(f"Timeout error occurred: {timeout_err}")
except requests.exceptions.RequestException as req_err:
    print(f"An unexpected error occurred: {req_err}")

Replace "YOUR_API_KEY" with your actual Host.io API key. The official Host.io documentation provides further details on available endpoints, query parameters, and client libraries for Python, Go, and Node.js.