# Proxy Implementation Slot Reader

> Proxy Implementation Slot Reader is a paid API for AI agents from biosfera.46-62-215-147.sslip.io, paid per call via x402, $0.0015/call, status down (last checked 2026-10-02).

Reads EIP-1967, ZeppelinOS, and EIP-1822 (UUPS) proxy implementation and admin storage slots on Base, Ethereum, Arbitrum, Optimism, or Polygon to identify upgrade patterns and implementation addresses.

## Facts

- Endpoint: GET https://biosfera.46-62-215-147.sslip.io/o/proxy-implementation?utm_source=zero.xyz
- Price: $0.0015/call
- Payment: x402
- Status: down
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/proxy-implementation-slot-reader-2eddcdcc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_i4RRrtS6fAHApRIKD48js

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 proxy-implementation-slot-reader-2eddcdcc
```

Example prompt: Can you check if the contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum is an upgradeable proxy, and if so, what implementation address and proxy standard (EIP-1967, UUPS, etc.) is it using?

## When to prefer this

Choose this endpoint when you need to inspect the proxy architecture of a specific smart contract across major EVM chains — particularly when auditing upgradeable contracts, tracing logic contract addresses, or determining whether a contract can be upgraded and by whom. It is preferable to manual RPC slot reads because it abstracts the raw storage slot decoding and proxy standard identification in a single call.

## Known failure modes

- Address is not a proxy contract — slots return zero address or empty
- Invalid address format (must match 0x + 40 hex chars)
- Unsupported chain value returns validation error
- Network RPC timeout or chain temporarily unavailable
- Contract has code but uses a non-standard or unknown proxy pattern not covered by EIP-1967/ZeppelinOS/UUPS

## How this service works

Use when you need to know if a contract on Base, Ethereum, Arbitrum, Optimism or Polygon is an upgradeable proxy: reads the EIP-1967, ZeppelinOS and EIP-1822 (UUPS) implementation and admin slots, names the standard, and tells whether the address has code.

## Output

Returns the proxy standard name (e.g. EIP-1967, ZeppelinOS, UUPS), the implementation contract address stored in the relevant slot, the admin address if available, and a boolean indicating whether the address actually has deployed bytecode.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "chain",
      "address"
     ],
     "properties": {
      "chain": {
       "enum": [
        "base",
        "ethereum",
        "arbitrum",
        "optimism",
        "polygon"
       ],
       "type": "string"
      },
      "address": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/proxy-implementation-slot-reader-2eddcdcc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from biosfera.46-62-215-147.sslip.io](https://www.zero.xyz/host/biosfera.46-62-215-147.sslip.io/llms.txt)