# how.is Domain Availability Check

> how.is Domain Availability Check is a paid API for AI agents from how.is, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-31).

Checks whether a domain name is registered by querying the registry over RDAP, returning availability status and first-year/renewal pricing when registrable.

## Facts

- Endpoint: POST https://how.is/v1/domain/available?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/how-is-domain-availability-check-86a64632
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__t2c0PVD2OlUkffBOrlp6

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 how-is-domain-availability-check-86a64632 -d '<json body>'
```

Example prompt: Can you check if mymintproject.io is available to register, and if so, what's the first-year and renewal price?

## When to prefer this

Use this endpoint when you need authoritative domain availability data sourced directly from the registry via RDAP, especially when pricing for registration and renewal matters. Prefer this over generic WHOIS lookups when you need a structured, machine-readable response with confidence scoring and standardised pricing data. Ideal for agentic workflows that need to decide whether to proceed with a domain purchase or alert a user to register a name.

## Known failure modes

- Domain with unsupported TLD may fall back to DNS-only check, returning null for availability with likely_available heuristic
- RDAP registry outage may result in degraded confidence or DNS fallback
- Malformed or invalid domain string returns validation error
- Some TLDs may not have pricing data available, returning null for price fields
- Network timeout on registry query may cause delayed or failed response

## How this service works

Is this domain name registered? Asked of the registry over RDAP, with the standard first-year and renewal price when it is free to register.

## Output

Returns a JSON object indicating whether the domain is available (true/false/null), when it was registered (if taken), the TLD suffix, the data source used (RDAP or DNS), a confidence score, and when available for registration, the first-year and renewal prices in USD along with the registrar name and any pricing caveats. Also includes a receipt with charge amount and settlement transaction hash.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "domain": {
   "type": "string",
   "maxLength": 253,
   "description": "A bare domain name, e.g. example.com"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "_shape": "data: available (true/false; null when only DNS could be checked, then likely_available), registered_on, suffix, source (rdap/dns), confidence, price{registration_usd, renewal_usd, registrar, note}, caveat."
  },
  "result": "Domain availability for the requested subject",
  "receipt": {
   "rail": "x402",
   "tool": "available",
   "charge_usd": 0.005,
   "settlement_tx": "0x…"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/how-is-domain-availability-check-86a64632/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from how.is](https://www.zero.xyz/host/how.is/llms.txt)