dotsweep vs Domainr

A domain search and status API with a twenty-value status vocabulary that covers aftermarket and registry-reserved states as well as plain availability.

Where Domainr is the better choice

Written first because a comparison written by one of the two products is worth nothing if it cannot say this.

• Twenty status values against our three, including aftermarket states such as marketed, transferable and expiring that we do not model at all.
• A documented state for its own uncertainty, which most of this list does not have.
• Years of production use behind other people's domain search tools, which is a track record we do not have.

Where dotsweep is different

• No key, no account, no signup. curl https://dotsweep.com/check/example.com works from a cold start.
• A 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.
• 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 /mcp over 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 Domainr?

Not at everything, and not for every job. Domainr does this better: Twenty status values against our three, including aftermarket states such as `marketed`, `transferable` and `expiring` that we do not model at all. 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. One thing worth knowing before choosing Domainr today: their own documentation says the v2 API is deprecated, that Domainr was acquired by Fastly in 2023, and that users are encouraged to migrate to the Fastly Domain Research API.

What Domainr documents

• https://domainr.com/docs/api, read 2026-07-30
• https://domainr.com/docs/api/v2/status, 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

All six compared side by side → · API and MCP reference →