6 Best WHOIS Domain Lookup APIs in 2026 (Free Tiers Compared)

Strongwell WHOIS Domain Intel API — Best for Developer Experience

Strongwell's WHOIS Domain Intel API earns the top spot for developers who need reliable domain registration data without enterprise complexity. The API supports both traditional WHOIS and modern RDAP protocols, automatically selecting the best data source for each TLD — so you don't need to manage the industry's ongoing protocol transition.

The response includes registrar information, creation/expiration/updated dates, nameservers, DNSSEC status, and available contact data in clean, structured JSON. DNS records are also included in the same API, eliminating the need for a separate DNS lookup service.

What puts Strongwell at #1 is the combination of modern protocol support, inclusive DNS data, and pay-per-query pricing with a free tier. Most competitors either charge enterprise rates (WhoisXML) or lack RDAP support (JsonWhois). Strongwell hits the sweet spot.

Try it: whois-domain-api.strongwell.workers.dev

WhoisXML API — Best for Enterprise Intelligence

WhoisXML API is the most feature-rich WHOIS data provider available. Their product suite spans WHOIS lookups, historical WHOIS records, reverse WHOIS searches, DNS lookups, domain reputation scoring, and 50+ other data products. For cybersecurity firms, brand protection agencies, and enterprise compliance teams, the depth is unmatched.

The trade-off is complexity and cost. Plans start at approximately $99/month (as of 2026 — check current pricing), and the product catalog can be overwhelming for developers who just need basic lookups. The free tier is 500 one-time credits rather than a recurring monthly allowance.

See our detailed WhoisXML vs JsonWhois comparison.

JsonWhois — Best Budget Monthly Plan

JsonWhois is the most affordable recurring-plan WHOIS API at $9/month. The API is simple and focused: send a domain, get back clean JSON with registration data. The 500/month free tier is adequate for testing and small-scale use.

The main limitations are partial RDAP support (not all TLDs covered) and no reverse WHOIS capability. For straightforward domain verification and monitoring on a budget, JsonWhois is the practical choice.

WhoisFreaks — Best for Bulk Operations

WhoisFreaks specializes in bulk WHOIS lookups — processing hundreds of domains in a single API call. If you manage a domain portfolio, run security scans across many domains, or need to enrich large datasets with registration data, the bulk endpoint saves significant integration effort.

Plans start at approximately $19/month. They also offer historical WHOIS and reverse WHOIS. The free tier (100 queries) is enough for evaluation but too small for production use.

Whoxy — Best for Reverse WHOIS

Whoxy's core strength is reverse WHOIS — finding all domains registered to a specific person, company, or email. Their database contains billions of historical WHOIS records. At approximately $2 per 1,000 queries (credit-based), the per-lookup cost is competitive for reverse searches specifically.

The lack of a free tier means you need to commit upfront. But for use cases like brand protection, competitive intelligence, and ownership research, Whoxy's reverse search is purpose-built and deeply capable.

IP2WHOIS — Best Free-Only Option

IP2WHOIS by IP2Location offers 500 free WHOIS lookups per month with no paid plan required. The data includes basic registration information — registrar, dates, and nameservers. RDAP support is limited, and the data depth is modest compared to commercial options.

For hobby projects, learning, and prototyping where you need occasional WHOIS data without any cost, IP2WHOIS fills the gap. For production applications, the data quality and coverage of paid options provide better reliability.