# Ethereum Contract Storage Slot Reader

> Ethereum Contract Storage Slot Reader is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-20).

Returns the 32-byte value stored at a specific storage slot of an Ethereum mainnet contract using eth_getStorageAt

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/eth-storage?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ethereum-contract-storage-slot-reader-ecfc94ad
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5CxJj5StUsNN4sc2EYFOP

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 ethereum-contract-storage-slot-reader-ecfc94ad -d '<json body>'
```

Example prompt: What's the 32-byte value stored at the EIP-1967 implementation slot 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc for the USDC contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum mainnet?

## When to prefer this

Use this endpoint when you need to read raw on-chain storage from an Ethereum mainnet smart contract without needing a full ABI or decoded output — especially for inspecting EIP-1967 proxy implementation slots, admin slots, or any known storage layout position. It is read-only, costs only $0.002 USDC, and requires no Ethereum node setup. Prefer the free sandbox endpoint (/v1/sandbox/eth-storage) for testing before paying.

## Known failure modes

- Invalid contract address format returns an error
- Invalid or malformed slot hex string returns an error
- Unsupported block tag or out-of-range block number returns an error
- Network or RPC node unavailability causes a 5xx error
- Non-contract address (EOA) returns 0x000...000 (no error, just empty storage)

## How this service works

Call when an agent needs the storage word at a slot for one Ethereum contract. Send contract, slot, and an optional block tag. Read-only eth_getStorageAt. No spend. Send JSON {"contract":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","slot":"0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc"}. Exact $0.002 USDC on Base. Try unpaid POST /v1/sandbox/eth-storage first.

## Output

A 32-byte hex-encoded value representing the raw contents of the specified storage slot for the given contract, as returned by eth_getStorageAt on Ethereum mainnet. The value is zero-padded to 32 bytes.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "slot": {
   "type": "string",
   "examples": [
    "0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc"
   ],
   "description": "Storage slot as a uint256 decimal or 0x-prefixed hex word of at most 32 bytes. Example: 0. The response value is 32 bytes."
  },
  "block": {
   "type": "string",
   "description": "Optional block number or tag latest, finalized, or safe. Example: latest. Omit it for latest. A JSON number such as 100 is accepted."
  },
  "contract": {
   "type": "string",
   "examples": [
    "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"
   ],
   "description": "Contract on Ethereum mainnet. Example: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913. eth_getStorageAt is read-only."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ethereum-contract-storage-slot-reader-ecfc94ad/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)