# PennyRail JSON Path GET

> PennyRail JSON Path GET is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Fetches a value from a JSON document by navigating a specified JSON path, delivered as a machine-readable paid endpoint via the x402 micropayment protocol.

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/json.get--json-path-get
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-json-path-get-36b94ba9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3QXLm_JeV3R5X2U6MBEJX

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-json-path-get-36b94ba9 -d '<json body>'
```

Example prompt: Can you extract the value at the JSON path '$.user.address.city' from this JSON object: {"user":{"name":"Alice","address":{"city":"Denver","zip":"80201"}}}?

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-call JSON path extraction over a micropayment rail (x402/USDC), especially in agent workflows where per-query billing is preferable to a subscription. It is well-suited for serverless or agentic pipelines that already handle x402 payments and need to extract specific fields from arbitrary JSON structures on demand.

## Known failure modes

- Invalid or malformed JSON path expression returns an error or empty result
- Input JSON document is missing or malformed, causing a parse failure
- Path does not exist in the document, returning null or an empty response
- Payment not processed (x402 payment required error) if micropayment header is missing
- Overly broad input schema means type mismatches may cause silent failures

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing the value found at the specified JSON path within the input document. The response is open-ended and may include the extracted value in any JSON-compatible format (string, number, object, array, null).

## 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-json-path-get-36b94ba9/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)