# Base Proxy Contract Detector

> Base Proxy Contract Detector is a paid API for AI agents from x402.agentindex.world, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-11).

Detects whether a Base mainnet contract is an upgradeable proxy (EIP-1967 transparent/UUPS, beacon, or EIP-1822) and returns its implementation address.

## Facts

- Endpoint: GET https://x402.agentindex.world/base/proxy?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-proxy-contract-detector-5460f6dd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iMl7u-t9W4yloVWNlUl1c

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 base-proxy-contract-detector-5460f6dd
```

Example prompt: Is the Base contract at 0x4200000000000000000000000000000000000010 an upgradeable proxy, and if so what's the implementation address?

## When to prefer this

Use this endpoint when you need to determine if a Base mainnet contract is a proxy and retrieve its underlying implementation address. Prefer this over generic Ethereum tools when specifically working on Base L2. Ideal for security audits, protocol integrations, or monitoring upgradeable contracts that follow EIP-1967, UUPS, beacon, or EIP-1822 standards.

## Known failure modes

- Address is an EOA (externally owned account), not a contract — returns not-a-proxy
- Contract is not a recognizable proxy pattern — returns no implementation address
- Invalid or malformed address input — returns validation error
- Contract exists but stores no implementation slot — ambiguous result
- RPC node unavailability causing lookup failure

## How this service works

Is this Base contract an upgradeable proxy? Proxy contract detection for EIP-1967 (transparent/UUPS), beacon, or EIP-1822 patterns, returning the implementation address.

## Output

Returns whether the given contract address is a proxy, the detected proxy pattern (EIP-1967 transparent, UUPS, beacon, or EIP-1822), and the resolved implementation contract address if applicable.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "address": {
   "type": "string",
   "title": "Address"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-proxy-contract-detector-5460f6dd/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.agentindex.world](https://www.zero.xyz/host/x402.agentindex.world/llms.txt)