This WHOIS API speaks RDAP — the structured, JSON-native successor to port-43 WHOIS — and returns one typed row per domain: registrar with its IANA id, creation, expiry and last-update dates, EPP status codes, delegated nameservers and whether the DNSSEC delegation is signed.
Send up to 25 domains per call, as bare names or full URLs. Each is routed to its TLD's authoritative registry through the rdap.org bootstrap, fetched over the TLS tier without a browser, and normalised into the same flat shape whether the answer came from Verisign or a tiny ccTLD registry. Domains that do not resolve are reported under failed and never billed — a lookup either produces a row or costs nothing. It is one corner of a domain-footprint triangle with the DNS lookup API and the Certificate Transparency API.
$0.0005 per delivered domain, up to 25 domains per run. Nothing delivered means nothing charged.
You post a domains array. URLs are stripped down to their registrable domain first, so a column of links pasted straight from a spreadsheet works without a cleanup pass.
For each domain the collector bootstraps the right registry via rdap.org — .com goes to Verisign, .io to the .io registry, and so on — then flattens the registry's RDAP response into one row. Three behaviours matter in practice:
expires means the same thing for a .com as for a .dev.failed, unbilled, instead of surfacing as rows full of nulls.domains is the one required field: an array of up to 25 bare domains or URLs per run. max_results (default 10, cap 25) trims how many of them are actually looked up — a cheap guard when the list is assembled by an upstream job you do not fully trust.
Each row carries registrar and registrar_iana_id, the created, expires and updated timestamps, the full status array of EPP codes, delegated nameservers, a boolean dnssec, and the url of the raw RDAP record if you ever need to argue with the source. Note what is absent: registrant name, email and address — registries redacted those years ago.
$0.0005 per delivered domain ($0.50 per 1,000). Nothing delivered means nothing charged, and the $2 monthly free credit covers roughly 4,000 domains here. Volume tiers take up to 30% off.
$0.0005 per resolved domain — $0.50 per 1,000. A weekly expiry sweep over a 2,000-domain portfolio costs a dollar a week; a one-off enrichment of a 50,000-domain lead list is $25. The monthly free allowance of $2 covers 4,000 lookups with no card on file.
Only delivered rows are billed. If half your list turns out to be unregistered typos, the invoice reflects the half that existed.
Straight answer: RDAP is a free, open protocol. For one domain, curl https://rdap.org/domain/example.com works today, unauthenticated, and if that is your whole need you should use it.
The paid product begins where the protocol's uniformity ends. Every registry runs its own RDAP server with its own rate limits, its own quirks and its own reading of the spec; some ccTLDs run none at all. Batch work therefore means bootstrap logic, per-registry throttling, retry policy, response normalisation and a decision about what to do with the misses — per registry. This collector compresses all of that into one request shape, one row schema, one failure bucket and one meter, on the same API key that runs your other sixty-plus collectors. You are paying half a cent per ten domains to not maintain a registry compatibility layer.
The whois command in a loop is how everyone starts, and it collapses on three predictable fronts:
If you want to keep your own tooling and just need the network, the residential proxies this rides on are sold separately. If you want rows, this endpoint is the shortcut.
Run your portfolio weekly and alert when expires crosses a threshold or status gains a code like redemptionPeriod. Catching one lapsed renewal a month early is worth more than a year of the collector's bill.
A domain's created date is a fast proxy for company age, and its registrar plus dnssec posture hints at operational maturity. Enrich a CRM export in one batch call per 25 rows.
For a pile of suspicious lookalikes, registration date is the tell — a bank's real domain is decades old, its impostor was registered on Tuesday. The failed bucket doubles as a free answer to which candidate typos are still unregistered.
Up to 25 domains per run; bigger lists are more runs, and independent runs parallelise up to your plan's request ceiling — from 60 a minute on pay-as-you-go to 1,200 on the largest tier. A minority of ccTLDs still operate no RDAP service; those land in failed, unbilled, rather than pretending. And to be explicit about scope: registrant contact details are not part of the output, because post-GDPR registries redact them at the source — no WHOIS product can honestly sell you that data anymore.
Legally this is comfortable territory: RDAP is a public protocol operated by the registries themselves precisely so this information can be looked up. Registry rate limits and terms still apply upstream — managing them is our problem, not yours.
Yes, in two senses. RDAP itself is free at the origin if you want to query registries one domain at a time. Here, the monthly $2 free allowance covers 4,000 domain lookups without a card — beyond that the rate is $0.0005 per resolved domain, with no subscription.
No, and be wary of any product claiming otherwise: registries redacted registrant contact data after GDPR. What you get is the operational record — registrar with IANA id, creation, expiry and update dates, EPP status codes, nameservers and DNSSEC — which is what expiry monitoring and enrichment actually need.
Post up to 25 domains per call, bare names or URLs. Each resolves against its TLD's authoritative registry over RDAP and comes back as one typed row; unresolvable names are listed under failed and not billed. A 10,000-domain list is 400 calls, which parallelise up to your plan's rate limit.
Same registration data, different plumbing. WHOIS is the 1980s protocol: plain text over port 43, no schema, aggressive per-IP limits. RDAP is its IETF-standardised replacement: JSON over HTTPS, served by the registries themselves. This collector queries RDAP and keeps the familiar WHOIS name because that is what everyone still searches for.