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Contract Storage Slot Reader
x402
Contract Storage Slot Reader is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Reads a raw 32-byte storage slot from an EVM smart contract and returns the value interpreted as hex, uint, address, and boolean
Price / call$0.001
Success—
StatusUnknown
How this service works
Read one 32-byte storage slot from a contract, the raw state under whatever the source code calls it. Returns the word as hex plus three readings of the same bytes - unsigned integer, address (low 20 bytes) and boolean - because a slot is untyped on chain and only the caller knows which it meant. Useful for proxy implementation slots, paused flags and any value the ABI does not expose. EVM chains: ethereum, base, polygon, arbitrum, optimism.
Output
Returns a JSON object containing the raw 32-byte slot value as a 0x-prefixed hex string, the same bytes decoded as an unsigned integer string, as an Ethereum address (low 20 bytes), and as a boolean, along with the contract address, network, slot index, and block reference used.
Example use cases
Proxy implementation address lookup
“What's the current implementation contract behind the proxy at 0x1234567890abcdef1234567890abcdef12345678 on Ethereum? Read its EIP-1967 slot 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc and give me the address.”
Check if contract is paused
“Is the contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum currently paused? Read storage slot 1 and interpret it as a boolean.”
Inspect hidden state at historical block
“What was stored in slot 0 of the contract 0x7Fc66500c84A76Ad7e9c93437bFc5Ac33E2DDaE9 on Ethereum at block 18000000 — show me the raw hex and the unsigned integer value.”
Technical details
Endpoint
GEThttps://agent402.tools/api/chain/storageWhen to prefer
Use this endpoint when you need to inspect raw on-chain contract state that is not exposed through the contract's public ABI — such as EIP-1967 proxy implementation slots, emergency pause flags stored in private variables, ownership slots, or any other untyped 32-byte storage word. It is especially valuable for proxy contract inspection, upgrade monitoring, and debugging. It covers Ethereum, Base, Polygon, Arbitrum, and Optimism. Prefer this over a full ABI call when the data you need is not in any public getter.
Side effects
- Invalid or non-checksummed contract address returns an error
- Slot index that is not a valid decimal or 0x-prefixed hex causes a parse error
- Unsupported network name returns a validation error
- Block number that doesn't exist yet or is beyond chain tip returns an error
- Contract at address doesn't exist (EOA) may return zero-value slot without error
- Network congestion may cause slow response for historical block queries
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"slot": "0x0",
"block": "latest",
"value": "0x0000000000000000000000000000000000000000000000000000000000000001",
"asBool": true,
"asUint": "1",
"address": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
"network": "base",
"asAddress": "0x0000000000000000000000000000000000000001"
}
}Tags
x402
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