# Beggar Bot Storage Slot Reader (Base mainnet)

> Beggar Bot Storage Slot Reader (Base mainnet) is a paid API for AI agents from beggar-bot-demand.beggarbot.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-11-04).

Reads raw EVM storage slots from smart contracts on Base, Ethereum, Optimism, Arbitrum, or Polygon, with support for mapping slots, proxy slot resolution, and optional block targeting.

## Facts

- Endpoint: GET https://beggar-bot-demand.beggarbot.workers.dev/v1/storageslot?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-04
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/beggar-bot-storage-slot-reader-base-mainnet-a6cff739
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LosA4iIhYYiTJjam2wNo_

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 beggar-bot-storage-slot-reader-base-mainnet-a6cff739
```

Example prompt: Can you read the EIP-1967 implementation slot of the contract at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base mainnet to find out what implementation address it's currently pointing to?

## When to prefer this

Use this endpoint when you need low-level EVM storage inspection for smart contracts — especially when you need to resolve proxy implementation addresses via EIP-1967 slots, inspect raw Solidity mapping values, or audit contract storage at a historical block. Prefer this over higher-level ABI-based call endpoints when the storage layout is known or when proxy slot patterns are needed without ABI decoding.

## Known failure modes

- Invalid or missing contract address returns an error
- Unsupported chain name returns a validation error
- Invalid slot format (not decimal, hex, or named constant) returns a parse error
- Block number not yet finalized or too far in the past may return an error
- Payment not received (HTTP 402) if x402 USDC payment on Base mainnet is not included
- Rate limiting or worker timeout for complex multi-slot requests

## How this service works

Paid: /v1/verify, /v1/risk, /v1/receipt cost $0.01 USDC per call on Base mainnet via x402 (payTo 0x719227f384b66BFEF00093D6d8d32fA9dC2B40e7); utilities analyze Base mainnet (USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) by default, network=base-sepolia optional; /v1/receipt/verify and discovery files are free. Operator: Beggar Bot.

## Output

A JSON object containing the raw value stored at the requested storage slot(s), with decoded fields where applicable. For named EIP-1967/ZOS slots, returns the resolved address or value. Mapping lookups return the computed slot and its value. Proxy detection may return additional proxy-related slots.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "keys": {
       "type": "string",
       "description": "csv keys (nested)"
      },
      "block": {
       "type": "string",
       "description": "optional block"
      },
      "chain": {
       "type": "string",
       "description": "base|ethereum|optimism|arbitrum|polygon"
      },
      "proxy": {
       "type": "string",
       "description": "1 to add proxy slots"
      },
      "slots": {
       "type": "string",
       "description": "csv decimal/0x slots or eip1967_impl|eip1967_admin|eip1967_beacon|zos_impl"
      },
      "contract": {
       "type": "string",
       "description": "0x address"
      },
      "mapping_slot": {
       "type": "string",
       "description": "base slot of mapping"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/beggar-bot-storage-slot-reader-base-mainnet-a6cff739/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from beggar-bot-demand.beggarbot.workers.dev](https://www.zero.xyz/host/beggar-bot-demand.beggarbot.workers.dev/llms.txt)