# WHOIS/RDAP Lookup API

> WHOIS/RDAP Lookup API is a paid API for AI agents from rdap-api-production.up.railway.app, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-30).

Returns domain registration data (registrar, registrant, dates, nameservers, status) for a given domain using the public RDAP protocol, paid per lookup via USDC on Base.

## Facts

- Endpoint: POST https://rdap-api-production.up.railway.app/check?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/whois-rdap-lookup-api-ffb3527e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_v_6V_HB31g4fpvT8u4fLB

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability whois-rdap-lookup-api-ffb3527e -d '<json body>'
```

Example prompt: Can you look up the WHOIS registration details for example.com — I want to know who registered it, when it expires, and which registrar holds it?

## When to prefer this

Prefer this endpoint when you need structured, machine-readable domain registration data without managing API keys or accounts, and are comfortable paying $0.005 USDC per lookup on Base mainnet. It is ideal for agents operating in Web3 contexts or x402 payment-enabled workflows. Choose this over traditional WHOIS tools when you need programmatic access with no rate-limit tiers tied to credentials, or when integrating into crypto-native pipelines.

## Known failure modes

- Domain not found / not registered — RDAP returns a 404-equivalent with no record
- Invalid domain format — request rejected due to malformed domain string
- TLD not supported — some ccTLDs may not expose RDAP endpoints
- Rate limiting from upstream RDAP registry — temporary lookup failure
- Payment failure on Base mainnet — call not processed if USDC transfer fails

## How this service works

Domain registration data via public RDAP protocol. No API key. No account. Pay per lookup on Base mainnet.

## Output

Returns structured RDAP registration data for the queried domain, including registrar name, registration and expiration dates, domain status flags (e.g. clientTransferProhibited), nameservers, and where available, registrant contact details. Data is sourced from the authoritative public RDAP registry for the domain's TLD.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "domain"
 ],
 "properties": {
  "domain": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/whois-rdap-lookup-api-ffb3527e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from rdap-api-production.up.railway.app](https://www.zero.xyz/host/rdap-api-production.up.railway.app/llms.txt)