# PennyRail npm Latest Package Version Lookup

> PennyRail npm Latest Package Version Lookup is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Fetches the latest published version of a given npm package name via a paid settlement endpoint

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/network/npm.latest--package-version-npm
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-npm-latest-package-version-lookup-565226e0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zvzWlEQQIK8iCj8-vqNSs

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-npm-latest-package-version-lookup-565226e0 -d '<json body>'
```

Example prompt: What's the latest published version of the 'axios' package on npm?

## When to prefer this

Use this endpoint when you need a quick, programmatic lookup of the latest npm package version and are operating in an x402-capable payment environment. Prefer this over direct npm registry calls when building agents that already use PennyRail's settlement infrastructure or when you need a normalized, machine-readable response without parsing raw npm API JSON.

## Known failure modes

- Unknown or misspelled package name returns an error or empty result
- Network timeout or upstream npm registry unavailability
- Malformed input string (empty or invalid package name) may return a validation error
- Payment settlement failure via x402 protocol prevents the call from completing

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing the latest published version string for the specified npm package, sourced from the npm registry.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-npm-latest-package-version-lookup-565226e0/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)