What makes a good free domain API?
The best free domain APIs offer generous monthly quotas, no credit card requirements, and access to core features. Look for APIs with at least 1,000 free requests per month and good documentation.
Why DomScan is #1
- Generous free tier: 10,000 credits/month with no credit card
- Broad TLD coverage: 1,100+ extensions supported
- Modern REST API with JSON responses and excellent docs
- Remote MCP integration for AI assistants
- All-in-one: availability, valuation, DNS, brand monitoring
Best Free Domain APIs - Top 10
DomScan
Our Pick Free Tier- Generous free tier: 10,000 credits/month with no credit card
- Broad TLD coverage: 1,100+ extensions supported
- Modern REST API with JSON responses and excellent docs
Domainr (Fastly)
Runner Up Free Tier- Backed by Fastly infrastructure
- Creative domain suggestions
- 10,000 precise or estimated status requests free each month
DNSlytics
Free Tier- Generous 2,500-request daily free tier
- Tracking code discovery
- Comprehensive reverse lookups
VirusTotal
Free Tier- Industry-leading threat detection
- Google-owned reliability
- Generous free tier
ViewDNS
Free Tier- Free web-based tools
- Wide range of reverse lookup tools
- Fast to evaluate from the browser
Name.com API
Free Tier- Free API access
- RESTful design
- No minimum requirements
HackerTarget
Free Tier- Security-focused toolset
- Subdomain discovery
- Affordable pricing
IP2WHOIS
Free Tier- Straightforward WHOIS lookup coverage
- Part of IP2Location ecosystem
- Useful alongside IP2Location data
Cloudflare Registrar
- Zero markup on domains
- Beta API can check up to 20 domains at once
- Free DNSSEC, CDN, and SSL
Host.io
Free Tier- Technology stack detection
- Related domains discovery
- Strong tie-in with the IPinfo ecosystem
Detailed Reviews
DomScan Review
DomScan is a developer-focused domain intelligence API built around real-time RDAP, broad TLD coverage, and agent integration through MCP.
Pros
- Broad 1,100+ TLD support
- Generous free tier (10K credits/month)
- Clean REST API with JSON responses
- Remote MCP server for AI assistants
Cons
- Newer service (less track record than older providers)
- No historical WHOIS data yet
Our Verdict
DomScan is our top pick for developers building domain-related applications in 2026. The combination of wide TLD coverage, generous free tier, and modern API design makes it the clear choice for most use cases.
Domainr (Fastly) Review
Domainr, now part of Fastly, pioneered creative domain suggestions and instant availability checking. While the original API is deprecated, the Fastly-powered service remains useful for domain discovery applications.
Pros
- Excellent domain suggestions
- Fastly infrastructure (fast and reliable)
- Good free tier for basic use
- Clean, simple API for basic use cases
Cons
- Original API deprecated
- Enterprise pricing not transparent
- Limited to availability (no valuation, DNS)
Our Verdict
Domainr is best suited for applications focused on domain discovery and creative suggestions. The Fastly backing ensures reliability, but the feature set is narrower than comprehensive alternatives.
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DNSlytics Review
DNSlytics emphasizes reverse lookups, tracking-code pivots, and DNS research, with a newer API v2 beta focused on datasets.
Pros
- Generous 2,500-request daily free tier
- Tracking code discovery
- Comprehensive reverse lookups
Cons
- API v2 coverage is still narrow in beta
- No domain availability API
- WHOIS data is not its core strength
Our Verdict
DNSlytics emphasizes reverse lookups, tracking-code pivots, and DNS research, with a newer API v2 beta focused on datasets.
VirusTotal Review
VirusTotal analyzes domains, URLs, and files for malware and malicious activity using 70+ antivirus engines and security tools.
Pros
- Industry-leading threat detection
- Google-owned reliability
- Generous free tier
Cons
- Security-only focus
- No domain registration features
- Rate limits on free tier
Our Verdict
VirusTotal analyzes domains, URLs, and files for malware and malicious activity using 70+ antivirus engines and security tools.
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ViewDNS Review
ViewDNS.info offers a broad toolbox of DNS, reverse IP, reverse MX, WHOIS, and IP history lookups for investigators and operators.
Pros
- Free web-based tools
- Wide range of reverse lookup tools
- Fast to evaluate from the browser
Cons
- Basic API compared to competitors
- No domain availability checking
- API is lighter than dedicated intelligence platforms
Our Verdict
ViewDNS.info offers a broad toolbox of DNS, reverse IP, reverse MX, WHOIS, and IP history lookups for investigators and operators.
Name.com API Review
First AI-native domain platform with modern REST API
Pros
- Free API access
- RESTful design
- No minimum requirements
- AI/automation projects, SaaS with domain features, modern API consumers
Cons
- Fewer TLDs
- Lower rate limits (20 req/sec)
- Registrar-focused, not intelligence
Our Verdict
Name.com stands out as the most developer-friendly registrar with its AI-native approach and modern API design. The free access and OpenAPI spec make integration straightforward. Ideal for automation projects.
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HackerTarget Review
HackerTarget provides security-focused DNS tools including subdomain discovery, reverse DNS, vulnerability scanning, and attack surface analysis.
Pros
- Security-focused toolset
- Subdomain discovery
- Affordable pricing
Cons
- Limited WHOIS capabilities
- No domain availability API
- Basic API documentation
Our Verdict
HackerTarget provides security-focused DNS tools including subdomain discovery, reverse DNS, vulnerability scanning, and attack surface analysis.
IP2WHOIS Review
WHOIS lookup API integrated with IP2Location ecosystem
Pros
- Straightforward WHOIS lookup coverage
- Part of IP2Location ecosystem
- Useful alongside IP2Location data
- Developers needing simple WHOIS lookups, IP2Location ecosystem users, fraud prevention teams
Cons
- No DNS lookup features
- Limited bulk and historical workflows
- Limited to WHOIS data
Our Verdict
IP2WHOIS offers a solid WHOIS lookup API with excellent TLD coverage and a reasonable free tier. The integration with IP2Location products is valuable for teams already in that ecosystem. For simple WHOIS lookups, it delivers, but the lack of historical data and bulk operations limits its appeal for advanced use cases.
Cloudflare Registrar Review
At-cost registration with a beta API for supported domains
Pros
- Zero markup on domains
- Beta API can check up to 20 domains at once
- Free DNSSEC, CDN, and SSL
- Cloudflare users, cost-conscious developers, supported-TLD registration automation
Cons
- Registrar API is still in beta
- Requires Cloudflare account, token, and registrant setup
- No renewal, transfer, or contact-update endpoints in the beta
Our Verdict
Cloudflare Registrar combines registry-price domains with a beta API for search, authoritative availability checks, and standard registration on supported extensions. Checks can show premium pricing, but the beta does not currently support premium registration. The beta also does not yet automate renewals or transfers, and registered domains must use Cloudflare's authoritative DNS.
Sources
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Host.io Review
Domain intelligence with technology detection and relationship mapping
Pros
- Technology stack detection
- Related domains discovery
- Strong tie-in with the IPinfo ecosystem
- Competitive analysis, technology profiling, lead generation, sales intelligence
Cons
- No domain availability API
- Monthly data updates, not true real-time refresh
- Lighter WHOIS depth than specialist providers
Our Verdict
Host.io excels at technology detection and domain relationship mapping. If you need to know what technologies a website uses or find related domains, it is excellent. However, for comprehensive WHOIS data or domain availability checking, specialized alternatives are better suited.
How We Rank
Our rankings combine hands-on product testing with public pricing pages, official API documentation, TLD or dataset coverage, documentation quality, and overall developer experience.
Last updated: August 2026