WhoisJSON vs WhoisXML API vs Whoxy: Which WHOIS API in 2026?

Introduction

Picking a WHOIS API looks simple until you start comparing. Pricing pages are inconsistent — some charge per request, some per credit, some per rate limit tier. Free tiers vary from 100 to 1,000 queries per month. And the actual data quality on a TLD your app cares about can differ dramatically between providers. This guide cuts through the noise with an honest, side-by-side comparison of the three most commonly evaluated WHOIS APIs in 2026: WhoisJSON, WhoisXML API, and Whoxy.

We cover pricing models, feature sets, RDAP support, and developer experience — and we end with a plain decision matrix so you can pick the right tool for your specific use case without reading marketing copy.

The Three APIs at a Glance

A quick overview before going into detail.

Pricing Model: Where the Real Difference Is

WhoisJSON — quota + rate limit

WhoisJSON uses a straightforward model: each plan comes with a monthly request quota and a rate limit. The higher your plan, the bigger your quota and the faster you can call the API.

Every plan includes all six endpoints — WHOIS, Reverse WHOIS, DNS, SSL certificate check, subdomain discovery, and domain availability — under the same API key. There are no per-feature upsells.

WhoisXML API — subscription (per-volume)

WhoisXML API charges per monthly request volume. Here are their published WHOIS API subscription rates:

WhoisJSON is roughly 10× to 30× cheaper depending on volume — the gap widens at scale. The free tier alone (1,000 req/mo) already covers what WhoisXML charges $30/mo for.

Where WhoisXML API justifies its premium: they offer unique products that no other provider matches — historical WHOIS archives going back years, zone file access, bulk data downloads, brand monitoring, and threat intelligence feeds. If any of those specific products are requirements for your use case, the higher cost may be warranted. For standard WHOIS lookups, DNS, or SSL checks, the cost difference is difficult to justify.

Whoxy — pay-as-you-go

Whoxy uses a credit-based, pay-as-you-go model. You buy query bundles upfront, no monthly commitment. Here are their published rates:

The no-commitment model suits sporadic, one-off projects. The trade-off is both scope and cost: Whoxy covers WHOIS lookup and reverse WHOIS only — no DNS, no SSL, no subdomain scanning — and the per-query rate is considerably higher than WhoisJSON's flat monthly pricing at comparable volumes (see comparison below).

Data Quality & TLD Coverage

All three providers ultimately query the same underlying WHOIS servers and, increasingly, RDAP endpoints. The differences come down to how the raw data is parsed, normalized, and returned to you.

RDAP support

RDAP (Registration Data Access Protocol) is the modern replacement for the legacy WHOIS protocol. It returns structured JSON natively, handles internationalized domain names correctly, and includes richer data — but only for TLDs whose registries have deployed it (most major ones have).

WhoisJSON automatically uses RDAP when available for a given TLD, and falls back to legacy WHOIS otherwise. When the source is RDAP, the response includes additional computed fields: age, expiration, statusAnalysis, and nsAnalysis. The source field in the response tells you which protocol was used.

WhoisXML API has partial RDAP coverage depending on the product. Whoxy uses traditional WHOIS parsing; RDAP is not supported at the time of writing.

GDPR and privacy redaction

Since GDPR came into force, registrant contact data for .com, .net, and many other TLDs is routinely redacted. All three providers handle this consistently by returning the available fields and omitting redacted ones. None of them can show you data that registrars have removed — any provider claiming otherwise should be approached with scepticism.

Response normalization

The raw WHOIS protocol returns unstructured plain text. Each provider parses it and maps it to a consistent schema. The field names, date formats, and object structure differ between providers — plan for a migration cost if you switch. WhoisJSON returns code created | , code expires | , code nameserver | , code registrar | , and code contacts | as standard fields across all TLDs.

API Design & Developer Experience

Authentication

WhoisJSON uses a single API key across all endpoints, passed as Authorization: Token=YOUR_API_KEY. One account, one key, access to everything.

WhoisXML API issues separate keys per product in many cases. If you use their WHOIS API plus their DNS Lookup API plus their SSL checker, you may end up managing multiple credentials and separate billing for each. This is manageable but adds overhead.

Whoxy uses a single key passed as a query parameter ( code apiKey | ), which is simpler than header-based auth from an HTTP perspective but slightly less secure for logging/tracing purposes.

Response format

All three return JSON. WhoisJSON and WhoisXML API also support XML output via a format parameter. Whoxy is JSON-only.

WhoisJSON's JSON schema is consistent across all TLDs — the same field names regardless of whether you are querying .com, .fr, or .io. Missing data (common on privacy-protected domains) is represented as null or absent rather than empty strings, which is easier to handle defensively in code.

Documentation

WhoisXML API has extensive documentation, reflecting their large product catalog. The volume of information can be overwhelming when you just want a simple WHOIS lookup.

WhoisJSON documentation is available at whoisjson.com/documentation and includes an interactive Swagger UI for all endpoints. Whoxy's documentation is minimal but sufficient given the scope of the product.

Rate Limits & Scalability

What happens when you exceed the limit

All three APIs return HTTP 429 when you hit a rate limit. The key differences are what comes next:

• WhoisJSON — on paid plans (Pro, Ultra), you have a monthly quota. Once exhausted, the API returns 429 until the month resets. On the Mega plan, there is no monthly quota — only the rate limit (requests per minute) applies. There are no automatic overage charges.
• WhoisXML API — credits are consumed per call. When your credits run out, you need to top up or wait for the monthly reset depending on your plan. No silent throttling — you get a clear error.
• Whoxy — pay-as-you-go means there is no hard rate-limit for running out of quota. You pay for what you use. The practical constraint is their per-minute request cap.

Which One Should You Choose?

Here is an honest breakdown by use case.

The honest summary: WhoisXML API is the right choice if you need historical WHOIS data, brand monitoring at scale, or enterprise data exports — and you are willing to pay the premium for it. Whoxy makes sense only for sporadic, one-off projects where you genuinely cannot commit to a monthly plan — the per-query cost is 3–7× higher than WhoisJSON at comparable volumes. For anything recurring, WhoisJSON is the more cost-effective option, and it covers DNS, SSL, subdomain, and monitoring under the same key.

Conclusion

There is no single "best" WHOIS API — it depends on what you are building. But for the majority of developers building SaaS applications, security tools, or domain intelligence pipelines, the combination of transparent fixed pricing, six endpoints under one key, and RDAP enrichment makes WhoisJSON a strong default starting point.

Start with the free tier (1,000 requests, no card required), and upgrade when your usage justifies it. If your needs grow beyond what any standard plan covers, the contact form is there for custom arrangements.