# PennyRail npm.latest Registry Lookup

> PennyRail npm.latest Registry Lookup is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-14).

Fetches the latest version metadata for an npm package from the npm registry via a paid settlement proxy

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/network/npm.latest--npm-registry
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-npm-latest-registry-lookup-8e44921a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_S__n1GdzhKi26LNy-ijP6

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-registry-lookup-8e44921a -d '<json body>'
```

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

## When to prefer this

Use this endpoint when you need to programmatically resolve the latest npm package version in an agent workflow that supports x402 micropayment settlement, particularly when you want a lightweight, pay-per-call alternative to self-hosting npm registry queries or using unauthenticated public endpoints.

## Known failure modes

- Package name not found in npm registry — returns error or empty response
- Malformed or missing 'input' field — validation error
- Payment settlement failure via x402 — 402 Payment Required if credentials are invalid
- Rate limiting or upstream npm registry unavailability — upstream timeout or 503

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing npm registry metadata for the queried package, including the latest version number, dist-tags, description, and other package-level fields as returned by 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-registry-lookup-8e44921a/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)