# Cited Brief Domain Check

> Cited Brief Domain Check is a paid API for AI agents from cited-brief.cited-brief.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-18).

Performs a comprehensive WHOIS/RDAP and DNS lookup for a given domain, returning registration status, DNS records, expiry, and email infrastructure details.

## Facts

- Endpoint: POST https://cited-brief.cited-brief.workers.dev/domain-check?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/cited-brief-domain-check-650793e6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dlt1mSybdVRTBgfiMiKLC

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 cited-brief-domain-check-650793e6 -d '<json body>'
```

Example prompt: Can you check the domain status for acmecorp.io — I want to know if it's registered, when it expires, and whether it has proper email records like SPF and DMARC set up?

## When to prefer this

Choose this endpoint when you need a single, rich snapshot of a domain's registration status and DNS health in one call — especially when you need both WHOIS/RDAP data and DNS records together. Ideal for agents automating domain portfolio monitoring, pre-send email deliverability validation, or competitive research. Prefer this over generic WHOIS tools when you need structured JSON output with computed fields like expires_in_days and receives_email.

## Known failure modes

- Invalid or malformed domain input returns an error or empty result
- Unregistered domains return registered: false with NXDOMAIN: true
- RDAP registry may not have data for some TLDs, leading to partial results
- DNS propagation delays may cause stale or missing records
- Payment failure over x402 protocol blocks the request before any lookup is performed

## How this service works

Pay-per-call web research tools for AI agents, paid in USDC over x402.

## Output

Returns a JSON object with full DNS records (A, AAAA, MX, NS, SPF, DMARC), RDAP-sourced registration metadata (registrar, creation date, expiry date, status flags), computed fields (age_days, expires_in_days, registered boolean, receives_email boolean), the checked_at timestamp, and any domain flags.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "domain": {
   "type": "string",
   "description": "Domain name or URL, for example example.com"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "dns": {
   "a": [
    "93.184.216.34"
   ],
   "mx": [],
   "ns": [
    "a.iana-servers.net"
   ],
   "spf": false,
   "aaaa": [],
   "dmarc": false,
   "nxdomain": false,
   "receives_email": false
  },
  "flags": [],
  "domain": "example.com",
  "source": "rdap",
  "status": [
   "client delete prohibited"
  ],
  "created": "1995-08-14T04:00:00Z",
  "expires": "2027-08-13T04:00:00Z",
  "age_days": 11000,
  "registrar": "Example Registrar, Inc.",
  "checked_at": "2026-10-12T21:00:00.000Z",
  "registered": true,
  "nameservers": [
   "a.iana-servers.net"
  ],
  "expires_in_days": 300,
  "registered_domain": "example.com"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/cited-brief-domain-check-650793e6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from cited-brief.cited-brief.workers.dev](https://www.zero.xyz/host/cited-brief.cited-brief.workers.dev/llms.txt)