# PennyRail OpenAPI Mock Response Validator

> PennyRail OpenAPI Mock Response Validator is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status down (last checked 2026-10-23).

Returns a mock OpenAPI response for a nano-payment-gated resource node endpoint, acting as a machine-readable settlement service stub

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/openapi.mock-response--mock-openapi-response?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-openapi-mock-response-validator-2e004e69
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_58dXBTx60j8_bdG1_gv2q

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-openapi-mock-response-validator-2e004e69 -d '<json body>'
```

Example prompt: Can you hit the PennyRail mock OpenAPI response endpoint with a test input object so I can see what a machine-readable settlement response looks like for my nano-payment integration?

## When to prefer this

Choose this endpoint when you need to test or prototype an x402 nano-payment workflow against a PennyRail resource node, or when you need a machine-readable mock OpenAPI response to validate client-side parsing logic without hitting a live settlement backend.

## Known failure modes

- Missing or malformed 'input' field returns a validation error
- Payment not included or insufficient USDC (0.001) triggers 402 Payment Required
- Endpoint may return generic or empty mock data with no guaranteed schema contract
- Vercel cold-start latency may cause occasional timeouts
- Mock response content may not reflect real settlement data

## How this service works

Machine-readable settlement service

## Output

Returns an arbitrary JSON object representing a mock OpenAPI response from the PennyRail settlement service node; the response schema is open (additionalProperties: true), so fields vary and represent a simulated machine-readable settlement or resource response.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-openapi-mock-response-validator-2e004e69/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)