Provide current and historical ownership information on domains / IPs. Identify all connections between domains, registrants, registrars, and DNS servers.
Internet Infrastructure Intelligence for OEMs
Ship the next feature of your cybersecurity product faster with ready-made blueprints and production-quality internet intelligence data.
With 15+ years of experience supporting cybersecurity OEMs, WhoisXML API helps teams reduce development time, accelerate go-to-market, and grow revenue.
15+ years
Of historical data
28.7 Billion+
WHOIS records
116 Billion+
DNS records
52,000+
Satisfied customers
Why OEM Vendors Choose WhoisXML API
Faster Go-to-Market
Launch products and features faster with clean, normalized, integration-ready internet intelligence data. Skip the complexity of collecting, processing, deduplicating, and correlating raw data sources internally.
Cost Savings
Avoid the massive cost of building and maintaining internet data pipelines in-house. Reduce the need for dedicated engineering teams, infrastructure, storage, and ongoing data processing by leveraging ready-to-use datasets.
Strategic Guidance
Work with internet intelligence experts who understand cybersecurity products inside out. Get tailored recommendations on the right datasets, correlations, and implementation approaches for your specific product and market.
Enterprise Reliability
Build on internet intelligence trusted by leading cybersecurity vendors worldwide. Benefit from high data coverage, consistent delivery, and enterprise-grade SLAs designed for production-scale environments.
Startups That Work With Us Keep Raising Money
$70M
Series C
Read the success story
$22M
Series B
Read the success story
$60M
Series D
$150M
Series D
$70M
Series C
$75M
Series C
$13.35M
Series B
$12.5M
Series B
Start Small, Scale Seamlessly
Whether you are validating a new product idea or supporting enterprise-scale workloads, WhoisXML API provides the infrastructure and flexibility to grow with your platform.
Start Fast
Build prototypes and MVPs quickly using easy-to-integrate APIs and free trial credits. Access a wide range of internet intelligence datasets without long onboarding cycles or upfront infrastructure investment.
Expand Easily
Add new pivots, enrichment layers, and intelligence checks as your product evolves. Extend functionality faster and more easily with consistently formatted datasets delivered through a unified data ecosystem.
Scale Reliably
Support large-scale production environments with regularly updated downloadable databases hosted directly in your infrastructure. Reduce API overhead, improve query performance, and deliver reliable experiences for enterprise customers and high-volume workloads.
Build on production-grade intelligence
Features You Can Build With Our Data
And so much more…
DNS Asset Discovery
Used in: EASM, CTEM, BAS, Penetration Testing, Vendor Risk Management, GRC
Discover connected internet assets and shadow IT infrastructure by pivoting from a small set of seed domains or IPs across historical WHOIS and DNS records, SSL certificates, subdomains, and IP intelligence.
Used in: EASM, CTEM, BAS, Penetration Testing, Vendor Risk Management, GRC
Discover connected internet assets and shadow IT infrastructure by pivoting from a small set of seed domains or IPs across historical WHOIS and DNS records, SSL certificates, subdomains, and IP intelligence.
Used in: TPRM, TIP, SOC Tools, Threat Hunting Solutions
Map related infrastructure by connecting domains, IPs, DNS records, SSL certificates, and historical ownership data to uncover shared patterns, relationships, and attacker-controlled assets.
Used in: Threat Intelligence Platforms, SIEMs, SOARs, DFIR, SOC Workflows
Enrich domains, IPs, and other indicators with correlated WHOIS, DNS, SSL, geolocation, and passive DNS intelligence to improve threat context and investigation accuracy.
Used in: EASM, CTEM, Vendor Risk Management, Threat Intelligence, Fraud Prevention, IAM, Anti-abuse Systems
Identify traffic originating from corporate VPNs, proxies, and anonymization infrastructure using NetFlow and active DNS data from the Internet Abuse Signal Collective.
Used in: TPRM, CTEM, SOC Tools
Map third-party infrastructure and software dependencies by analyzing owned IP inventories against NetFlow data, identifying repeated asset-to-peer IP communications and ports, and using DNS data to explain intelligence for clearer naming, context, and attribution.
Used in: CTEM, ASM/EASM, SOC, Brand Protection Tools
Continuously monitor owned domains for DNS, WHOIS, SSL, and email security changes to detect misconfigurations, soon-to-expire assets, and suspicious infrastructure drift.
Used in: DNS Filtering, Web Gateways, EDR/XDR, SOC Tools
Monitor newly registered and observed domains, enrich them with reputation, DNS, WHOIS, and infrastructure signals, and automatically score or block high-risk domains commonly associated with phishing, malware delivery, and attacker staging activity.
Discover newly observed domains that were registered a while ago but never received traffic until recently using passive DNS signals.
Used in: EDR/XDR, SOC Tools, Threat Intelligence Platforms
Monitor NetFlow traffic for connections to external hosts and enrich this data with DNS, SSL certificates, infrastructure relationships, and reputation signals to identify communications with botnets, flag malware callbacks, and uncover related attacker-controlled infrastructure.
And so much more…
Free Cybersecurity Blueprints eBook
Get actionable blueprints for building cybersecurity capabilities with Internet intelligence data.
From domain ownership expansion and DNS monitoring to infrastructure footprint mapping and passive DNS shadow IT discovery, this ebook provides detailed blueprints with implementation steps, and operational best practices that product teams can immediately adapt for real-world security platforms.
Frequently Asked Questions
WhoisXML API provides over 20 different internet intelligence datasets, including historical WHOIS and DNS data, subdomains, SSL certificates, IP geolocation, ASN and netblock data, newly registered domains, predictive threat intelligence, abuse signals, and more. All data is normalized, enriched, standardized, and designed for direct use in cybersecurity products and workflows.
Our datasets are continuously normalized, deduplicated, and correlated across multiple internet intelligence sources to maximize coverage and usability.
For example, we combine WHOIS and RDAP data to improve domain ownership coverage and maintain production-ready datasets that reduce engineering overhead for cybersecurity vendors. For passive DNS, we flag wildcard records. That allows for discarding wildcard noise, significantly reducing false positive rates.
Some data products, such as geospatial IP intelligence with physical device location data or First Watch predictive threat intelligence that highlights domains registered with malicious intent, are unique — other vendors do not offer similar datasets.
WhoisXML API has over 15 years of experience gathering internet intelligence data and implementing it across a wide variety of cybersecurity products. In addition to the data itself, we are happy to support our partners by providing implementation guidance, cybersecurity blueprints, technical support, and service-level agreements (SLAs).
WhoisXML API supports multiple delivery methods:
- Real-time APIs
- Bulk APIs
- Downloadable datasets
- Feeds & streaming feeds
Yes. Many customers begin by prototyping with APIs and later transition to downloadable datasets or enterprise delivery options as product usage and query volumes grow. WhoisXML API supports both rapid experimentation and large-scale production deployments.
WhoisXML API has been collecting, processing and normalizing WHOIS, DNS, and other internet intelligence data for over 15 years. In addition to that, selected datasets incorporate intelligence from trusted partners, members of the Internet Abuse Signal Collective (IASC), helping expand coverage and deliver unique security signals.
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