# PennyRail URL JSON-to-Query Builder

> PennyRail URL JSON-to-Query Builder 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).

Converts a JSON object into URL query string parameters for use in HTTP requests

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/url.json-to-query--build-query-params
- 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-url-json-to-query-builder-8daf3d17
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_W8TbP_-1DpLlDT8y_8XHU

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-json-to-query-builder-8daf3d17 -d '<json body>'
```

Example prompt: Take this JSON object — {"search": "laptops", "maxPrice": 1200, "inStock": true} — and convert it into a URL query string I can append to an API endpoint.

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call microservice to convert JSON objects into URL query strings without deploying your own serialization logic. Useful in agent workflows that need to bridge JSON-based data structures with legacy GET-only APIs or URL-based routing systems.

## Known failure modes

- Missing or malformed 'input' field returns a validation error
- Deeply nested or complex objects may not serialize predictably
- Arrays within the JSON may require specific serialization format (e.g. repeated keys vs bracket notation)
- Payment failure or insufficient USDC balance returns HTTP 402
- Non-serializable values (functions, circular references) may cause errors

## How this service works

Machine-readable settlement service

## Output

Returns a query string representation of the input JSON object, with keys and values URL-encoded and formatted as standard query parameters (e.g. key1=value1&key2=value2), ready to be appended to a URL.

## 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-url-json-to-query-builder-8daf3d17/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)