# PennyRail JSON Field Omission Service

> PennyRail JSON Field Omission Service is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-21).

Accepts a JSON object and returns it with specified fields omitted, delivered as a machine-readable settlement response

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/json.omit--omit-json-fields?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-json-field-omission-service-4097acff
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_j1Gf8yI4Dzn3AzjQ9WS17

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-field-omission-service-4097acff -d '<json body>'
```

Example prompt: Take this JSON object and give me back a version with the 'password' and 'ssn' fields removed: {"name":"Alice","password":"secret","ssn":"123-45-6789","email":"alice@example.com"}.

## When to prefer this

Use this endpoint when you need a lightweight, pay-per-call JSON field omission operation without standing up your own transformation service. It is ideal for agents that occasionally need to strip sensitive or unwanted keys from small JSON payloads as part of a pipeline, and where the $0.001 USDC micropayment cost per call is acceptable.

## Known failure modes

- Missing or malformed 'input' field returns a validation error
- Non-object input value causes a schema rejection
- Payment failure (402) if x402 micropayment is not settled before the call
- Unrecognized field names to omit may be silently ignored rather than flagged
- Vercel cold-start latency on first invocation

## How this service works

Machine-readable settlement service

## Output

A JSON object identical to the input but with the specified fields removed; the response schema is an open object with any remaining key-value pairs from the original input.

## 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-field-omission-service-4097acff/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)