dotsweep vs WhoisJSON
A WHOIS and availability API with a small JSON response, sold on how little you have to parse.
| dotsweep | WhoisJSON | |
|---|---|---|
| No key | YesNo key, no account, no signup. curl https://dotsweep.com/check/example.com works from a cold start. |
NoEvery call requires an Authorization: TOKEN=YOUR_API_KEY header. The token is free when you create an account. |
| Admits doubt | YesA registry that is throttled, timed out or publishes no RDAP resolves to estimated, never available. A 429 from one registry does not become a confident answer about another one on the same host. |
Not documentedTheir documentation describes the endpoint as giving "Real-time registration status, whether a domain is available or already registered", and the page carries no sample payload. We found no documented third state for a registry that could not be reached, and we did not test it. |
| Renewal + term | YesRegistration and renewal are separate figures, a first-year discount is flagged as a promotion, and an extension the registry sells only in multi-year terms is multiplied out so the leading number is what leaves your account. | Not documentedNot documented on the page we read. |
| Eligibility | Partly38 extensions have had their registry policy read, 33 of them with an eligibility rule, each citing the registry's own page and the date it was read. An extension that is not in that set asserts nothing. | Not documentedNot mentioned on the page we read. |
| Free tier | Yes120 requests a minute, counted as requests rather than domains, and a batch endpoint carrying 20 domains each. Edge cache hits are not counted at all. | Partly1,000 requests a month across all their services, rate-limited to 20 a minute. |
| Assistant-ready | YesAn MCP server at /mcp over the same handlers, plus /llms.txt, so an assistant can call it without a wrapper. |
Not documentedWe found no MCP server or assistant-facing reference on the pages we read. |
Where WhoisJSON is the better choice
Written first because a comparison written by one of the two products is worth nothing if it cannot say this.
- A stated monthly allowance of 1,000 requests. Ours is a per-minute rate limit with no published monthly total, which is harder to plan against.
- Several other lookup services under the same key and the same allowance.
- They publish a comparison of this whole category, which is more than most vendors here do and more than we did until now.
Where dotsweep is different
- No key, no account, no signup.
curl https://dotsweep.com/check/example.comworks from a cold start. - A registry that is throttled, timed out or publishes no RDAP resolves to
estimated, neveravailable. A 429 from one registry does not become a confident answer about another one on the same host. - Registration and renewal are separate figures, a first-year discount is flagged as a promotion, and an extension the registry sells only in multi-year terms is multiplied out so the leading number is what leaves your account.
- 38 extensions have had their registry policy read, 33 of them with an eligibility rule, each citing the registry's own page and the date it was read. An extension that is not in that set asserts nothing.
- An MCP server at
/mcpover the same handlers, plus/llms.txt, so an assistant can call it without a wrapper.
The unconfirmed-rather-than-available rule is the one worth explaining,
because it is the only wrong answer in this category that costs somebody money.
A registry that is rate-limiting you often phrases the refusal in words a parser
reads as "no such domain", so the naive result of a throttled lookup is a
confident "available" for a name somebody already owns. dotsweep asserts this in
its test suite in both engines, and marks the answer estimated
instead.
Is dotsweep better than WhoisJSON?
Not at everything, and not for every job. WhoisJSON does this better: A stated monthly allowance of 1,000 requests. Ours is a per-minute rate limit with no published monthly total, which is harder to plan against. dotsweep answers a different question: it needs no key or account, it returns the renewal price and the minimum term rather than the advertised first-year figure, it says who is allowed to register the extension, and it reports a throttled or unreachable registry as unconfirmed rather than available.
What WhoisJSON documents
- https://whoisjson.com/documentation, read 2026-07-30
- https://whoisjson.com/blog/best-domain-availability-api, read 2026-07-30
How we know this, and what we did not do
Every claim about another product here was read from that vendor's own documentation, and each one is listed with the page and the date it was read. No figure comes from a review, a listicle or another comparison.
We did not benchmark any of these services. Nothing on this page reports a measurement, and where a row says "not documented" it means their documentation did not answer the question and we did not test it. It is not a quiet way of saying no. Getting that distinction wrong is how the rest of a comparison table stops being worth reading, and it is the same rule the rest of this site follows about extensions whose registry policy nobody has read.
If something here is out of date or wrong, the date next to it is there so you can tell which, and support@dotsweep.com reaches a person.
Check a name without signing up for anything
curl https://dotsweep.com/check/example.com