# Multichain RPC Proxy Implementation Lookup

> Multichain RPC Proxy Implementation Lookup is a paid API for AI agents from multichain-rpc.clankerceo.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Detects whether a smart contract on EVM chains is a proxy and resolves the underlying implementation address using EIP-1967 and similar patterns.

## Facts

- Endpoint: GET https://multichain-rpc.clankerceo.workers.dev/proxy-implementation
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/multichain-rpc-proxy-implementation-lookup-fdf0431a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VVLN1CJZjBTwFH6LzYzZ-

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 multichain-rpc-proxy-implementation-lookup-fdf0431a
```

Example prompt: Is the contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum a proxy, and if so what's its implementation address?

## When to prefer this

Choose this endpoint when you need to determine if a smart contract is upgradeable and resolve its actual logic contract across Base, Polygon, Arbitrum, Optimism, or Ethereum. It is purpose-built for proxy detection using recognized patterns like EIP-1967 and is priced per-call at $0.002 USDC, making it cost-effective for spot lookups. Prefer it over general-purpose RPC calls when you want a structured, pre-parsed proxy resolution result rather than raw storage slot reads.

## Known failure modes

- Invalid or unrecognized chain name returns an error — use supported values: base, polygon, arbitrum, optimism, ethereum
- Malformed or checksumless contract address returns a parsing error
- Contract is not a proxy — returns is_proxy: false with no implementation address
- RPC node unavailable for the target chain — may return a 5xx or timeout
- Non-existent contract address (no bytecode) may return is_proxy: false or an error
- Payment failure via x402 protocol blocks the request with a 402 response

## How this service works

Cheap, factual EVM chain lookups priced per call in USDC. Base, Polygon, Arbitrum, Optimism and Ethereum.

## Output

A JSON object containing: the queried chain name, the queried contract address, whether the contract is a proxy (is_proxy boolean), the detected proxy pattern (e.g. 'eip1967.implementation'), and the resolved implementation contract address if a proxy was detected.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "queryParams"
   ],
   "properties": {
    "type": {
     "enum": [
      "http"
     ],
     "type": "string"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "chain": {
       "type": "string"
      },
      "address": {
       "type": "string"
      }
     }
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "enum": [
      "json"
     ],
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "chain": "base",
  "address": "0x…",
  "pattern": "eip1967.implementation",
  "is_proxy": true,
  "implementation": "0x…"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/multichain-rpc-proxy-implementation-lookup-fdf0431a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from multichain-rpc.clankerceo.workers.dev](https://www.zero.xyz/host/multichain-rpc.clankerceo.workers.dev/llms.txt)