# PennyRail Chain ID Lookup

> PennyRail Chain ID Lookup is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-22).

Looks up blockchain chain information by chain ID or identifier string via a machine-readable settlement endpoint

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/chain.info--chain-id-lookup?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-chain-id-lookup-cd00a186
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_YbAYGDnyCMsTtHoSIO7mx

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-chain-id-lookup-cd00a186 -d '<json body>'
```

Example prompt: Can you look up the chain info for Ethereum mainnet using chain ID 1 on PennyRail?

## When to prefer this

Use this endpoint when you need a quick, machine-readable lookup of blockchain chain metadata by chain ID and are operating in an x402 micropayment-enabled agent environment. It is appropriate when you need to resolve a numeric or string chain identifier to human-readable network details programmatically at low cost ($0.001 USDC per call).

## Known failure modes

- Unknown or unsupported chain ID returns an error or empty result
- Malformed input string causes a validation failure
- Service unavailability on the Vercel deployment returns a 5xx error
- Payment failure via x402 protocol results in a 402 response and no data returned
- Chain ID exists but metadata is incomplete or not indexed

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing chain metadata for the queried chain identifier, such as chain name, network type, chain ID number, and other relevant network parameters. The response schema is open-ended and may include additional fields depending on the chain.

## 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-chain-id-lookup-cd00a186/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)