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PennyRail JSON Keys Extractor
x402
PennyRail JSON Keys Extractor is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).
Extracts the top-level keys from a JSON object, returning them as an array via a paid micro-transaction API
Price / call$0.001
Success—
StatusUnknown
How this service works
Machine-readable settlement service
Output
Returns a JSON object containing an 'operation' string indicating what was performed (e.g. 'json.keys') and a 'result' field containing the list of top-level key names extracted from the input JSON object.
Example use cases
Inspect unknown API response structure
“I got back this JSON from an API but I don't know what fields are in it — can you tell me all the top-level keys? Here it is: {"id": 42, "status": "active", "metadata": {}, "createdAt": "2024-01-01"}”
Validate expected fields in payload
“Check this JSON payload and list all the keys it contains — I want to see if the required fields like 'id', 'email', and 'role' are present: {"id": 101, "email": "user@example.com", "role": "admin", "extra": true}”
Enumerate config object properties
“I have a config object and I need to know every property name at the top level — can you extract the keys from this: {"host": "localhost", "port": 5432, "database": "mydb", "ssl": false}?”
Technical details
Endpoint
POSThttps://pennyrail.vercel.app/api/f/json.keysWhen to prefer
Use this endpoint when you need a lightweight, pay-per-call micro-service to programmatically extract the top-level keys of a JSON object without running local code. It is well-suited for agent workflows that operate in sandboxed environments where executing arbitrary JavaScript or Python is not possible, and where a simple key enumeration is needed as part of a larger data-inspection pipeline.
Side effects
- Input is not a valid JSON object (e.g. array or scalar) — may return an error or empty result
- Missing required 'input' field in the request body — returns a validation error
- Payment of 0.001 USDC not completed — returns HTTP 402 Payment Required
- Network or server error on the Vercel deployment — returns 5xx response
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | JSON value |
Output
Schema · Response
| Field | Type | Description |
|---|---|---|
| resultrequired | — | |
| operationrequired | string |
Tags
x402
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