Domain Availability Checker /check APIPOST /check · x402 API by Domain Availability Checker
Give this API up to 10 domain names and it will tell you whether each one has a registration record on file with the official registry. It uses RDAP — the modern, structured replacement for WHOIS — so there is no messy free-text parsing. Each domain comes back labeled 'registered', 'unregistered', or 'indeterminate' (when the registry does not support RDAP for that ending). Important: 'unregistered' means no record was found, which usually means the name is available — but reserved or premium names can also return no record. This API tells you registration status only; it does not tell you price, premium status, or whether a registrar will actually let you buy the name.
What does this x402 API do?
Domain Availability Checker /check API. This is an x402-gated POST API resource from Domain Availability Checker. TOLL·402 did not invoke this route automatically because doing so was not considered safe. No normalized USD price is recorded; the listing names Base and Solana. No settled paid call has been verified.
- Published price
- No normalized USD price is recorded
- Networks
- Base · Solana
- Latest evidence
- TOLL·402 did not invoke this route automatically because doing so was not considered safe
- Resource ID
- 8d89a90115ed0d744dd778ca
Start with a quote-only recipe. Payment signing stays in your project.
const response = await fetch("https://domain-availability-checker.underscoredone.com/check", {
method: "POST",
headers: { "content-type": "application/json" },
body: JSON.stringify({
"type": "http",
"method": "POST",
"bodyType": "json",
"bodyFieldNames": [
"domains"
],
"pathParamNames": [],
"queryParamNames": []
}),
});
console.log(response.status);
console.log(Object.fromEntries(response.headers));
console.log((await response.text()).slice(0, 1000));
// A valid 402 is a quote, not a completed paid call.Review the provider input schema before running this non-read-only method. No payment code is included.
- Exact route checked
not safely testable · potentially-mutating-method:POST
- Origin reachable
HEAD https://domain-availability-checker.underscoredone.com/ returned 301.
- Observed in cdp-bazaar
The registry record was observed and retained with provenance.
What evidence supports this listing?
Each record has an exact-route quote outcome. Unresolved templates and potentially mutating methods are labeled instead of being invoked without provider-specific test input. A quote is still separate from a settled paid call. Read the discovery and verification methodology →
Which networks and payment options does it accept?
The normalized listing price is No normalized USD price is recorded. Raw protocol requirements remain visible below for implementation and audit use.