# Base Storage Slot Reader

> Base Storage Slot Reader 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).

Reads a raw 32-byte storage slot value from any contract on Base mainnet via eth_getStorageAt, returning the value as hex and unsigned integer.

## Facts

- Endpoint: GET https://x402.agentindex.world/base/storage?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-storage-slot-reader-babb2150
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_V1TmlVhlCxcV1mH1k6Wo9

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-storage-slot-reader-babb2150
```

Example prompt: What is the raw value stored in slot 0 of the contract at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base mainnet?

## When to prefer this

Use this endpoint when you need raw EVM storage inspection on Base mainnet — particularly useful for reading proxy implementation slots, inspecting packed storage variables, or auditing contract state that isn't exposed via a public getter. Prefer this over contract introspection endpoints when you know the exact storage layout and need the raw bytes rather than ABI-decoded values.

## Known failure modes

- Invalid contract address format returns an error
- Slot index out of valid range may return zero rather than an error
- Non-contract (EOA) address returns zero for all slots
- Network congestion may cause slow or failed RPC responses
- Missing required parameters (address or slot) returns a validation error

## How this service works

Read a contract storage slot on Base mainnet via eth_getStorageAt - the raw 32-byte value, decoded as hex and unsigned integer, zero-filled if unset.

## Output

Returns the 32-byte storage slot value as a zero-padded hex string and its equivalent unsigned integer representation. If the slot has never been written to, it returns a zero value (0x0000...0000 / 0).

## Request schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-storage-slot-reader-babb2150/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)