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WhoisXML API Domain Availability API

Freemium#12 of 34 in Domain Search Tools

WhoisXML API Domain Availability API: A focused availability API for server-to-server domain registration checks. Ranked #12 of 34 in Domain Search Tools by our editors (6.3/10); pricing: Free plan; best for server-to-server availability checking.

6.3/10Editor score

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WhoisXML API Domain Availability API6.3 Visit WhoisXML API

At a glance

Editor score
6.3 / 10
Pricing
Free plan
Best for
Server-to-server availability checking
Free plan
Yes
Facts checked
20 Sep 2026

WhoisXML API Domain Availability API screenshot

Where it wins
- REST API supports JSON and XML responses
- DNS-only and DNS-and-WHOIS checking modes
- Automatic, RDAP, or WHOIS protocols with up to 30 requests per second
Where it doesn't
- API-only product with no broader end-user search interface
- Paid or customized packages require a sales-led process
- Free access includes only a limited number of complimentary queries

Our verdict on WhoisXML API Domain Availability API

WhoisXML API Domain Availability API is a server-to-server service for checking whether domain names are available for registration. It is designed for registrars, domain investors, cybersecurity teams, and other businesses that need availability data inside their own systems. REST API access supports JSON and XML responses, while the service checks generic and country-code top-level domains using DNS and WHOIS-based methods. The vendor says its WHOIS database is updated daily.

The Free plan includes API access and JSON or XML responses, making it suitable for evaluating an integration or handling limited query needs. New accounts receive a limited number of complimentary queries before paid usage or customized packages are required. Paid and customized solutions are available through sales. For platform fit, the API can support server-to-server workflows without requiring a separate application interface, but teams need technical resources to connect it to their own software.

Its strongest focus is availability checking rather than domain discovery or bulk-search workflows. The API offers DNS-only availability checking, DNS-and-WHOIS checking, and automatic, RDAP, or WHOIS existence-check protocols. Request rates can reach up to 30 requests per second, which fits many automated lookup scenarios. The main trade-off is scope: organizations seeking a standalone search experience, broader discovery tools, or a self-serve paid plan should consider a different type of product. Choose this API when integration flexibility and protocol options matter most; avoid it when the primary need is an end-user domain search product.

WhoisXML API Domain Availability API pricing

Plans Free planFreemium A usable free plan; paid tiers unlock the limits above. Prices re-checked Sep 2026.

See plans on domain-availability.whoisxmlapi.com

All 2 WhoisXML API Domain Availability API plans and prices →

WhoisXML API Domain Availability API fact sheet

Free plan	Yes
Paid from	Not verified
TLD count	Not verified
Bulk search limit	Not verified
Domain variations	Not verified
Bulk upload	Not verified
Export options	Not verified
API access	Yes
Deployment	Cloud
Compliance & security	GDPR
Support	Email, Phone, Docs
Built for	Small business, Mid-market, Enterprise (editorial estimate)
Pricing	Free plan (source)
Website	domain-availability.whoisxmlapi.com
Facts checked	20 Sep 2026

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Featured on iTechGuides

WhoisXML API Domain Availability API is listed in our Domain Search Tools directory. Add the badge to your site — it links back to this page.

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Reviewed by iTechGuides Editors · Editorial team · Updated Sep 2026

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Last updated 28 Sep 2026 · How we research and update