# PennyRail URL Domain Lookup

> PennyRail URL Domain Lookup is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status down (last checked 2026-10-22).

Resolves and processes a URL's domain through a machine-readable settlement service, returning operation result data for the given URL input

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/f/url.domain?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-url-domain-lookup-c997f062
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__Zbk8JCUOnUA8QXnZ-H3y

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 pennyrail-url-domain-lookup-c997f062 -d '<json body>'
```

Example prompt: Can you resolve the domain for https://example.com and give me the machine-readable details about it?

## When to prefer this

Use this endpoint when you need a lightweight, pay-per-call ($0.001 USDC) machine-readable domain lookup for a given URL and want x402 micropayment-compatible infrastructure without a subscription. Prefer over heavier DNS APIs when cost-per-call efficiency and agent-native payment rails matter.

## Known failure modes

- Invalid or malformed URL input returns an error
- Unreachable or nonexistent domain may return empty or null result
- Missing required 'input' field causes request rejection
- Payment failure (insufficient USDC) blocks the call
- Timeout if the domain resolution takes too long

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing an 'operation' string describing what was performed, and a 'result' field with the domain-level data resolved for the given URL. Additional fields may be present.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "string",
   "description": "string URL"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "operation",
  "result"
 ],
 "properties": {
  "result": {},
  "operation": {
   "type": "string"
  }
 },
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-url-domain-lookup-c997f062/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pennyrail.vercel.app](https://www.zero.xyz/host/pennyrail.vercel.app/llms.txt)