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On-Chain Storage Slot Reader
x402
On-Chain Storage Slot Reader is a paid API for AI agents from x402-agent-store.rileycraig14.workers.dev, paid per call via x402, $0.09/call, status unknown (last checked 2026-09-14).
Reads a specific storage slot value from a smart contract on EVM-compatible chains (Base, Ethereum, Optimism, Arbitrum, Polygon, Gnosis)
Price / call$0.09
Success—
StatusUnknown
How this service works
Read any raw contract storage slot via eth_getStorageAt — the low-level read auditing, proxy-resolution and advanced trading agents make to inspect contract state directly. Pass address + slot. Across Base, Ethereum, Optimism, Arbitrum, Polygon, Gnosis. Free public RPC; undercuts onesource at $0.001 on 6 chains.
Output
Returns a JSON object containing the queried contract address, chain name, storage slot index, and the raw 32-byte hex value stored at that slot on the specified EVM chain.
Example use cases
Verify proxy upgrade admin slot
“Can you check storage slot 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103 on the contract 0x1234567890abcdef1234567890abcdef12345678 on Ethereum? I want to confirm who the admin is for this upgradeable proxy.”
Inspect packed storage on Arbitrum
“I need to read slot 1 from the contract 0xFd086bC7CD5C481DCC9C85ebE478A1C0b69FCbb9 on Arbitrum — I'm trying to figure out what values are packed in there without using an ABI.”
Check implementation slot on Base
“What's the raw value at storage slot 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc for the contract 0x6B175474E89094C44Da98b954EedeAC495271d0F on Base? I want to verify which implementation address this proxy is pointing to.”
Technical details
Endpoint
GEThttps://x402-agent-store.rileycraig14.workers.dev/chain/storageWhen to prefer
Use this endpoint when you need low-level raw storage reads from EVM smart contracts without requiring an ABI, especially across multiple chains (Base, Ethereum, Optimism, Arbitrum, Polygon, Gnosis). Prefer it over ethers.js or direct RPC calls when you want a pay-per-use, keyless HTTP interface that accepts USDC via x402. Ideal for agents that need to inspect contract internals, verify upgrade proxy slots, or read packed storage values programmatically.
Side effects
- Invalid contract address format returns an error
- Storage slot not found or unoccupied returns 0x000...000
- Unsupported chain name returns a validation error
- Malformed hex slot value may cause a parse error
- Network RPC unavailability causes a timeout or 5xx error
- Payment failure via x402 prevents the call from being processed
Input
{
"input": {
"type": "http",
"method": "GET",
"output": {
"type": "object"
},
"queryParams": {
"slot": "0x0",
"chain": "ethereum",
"address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"
}
}
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
{
"slot": "0x0",
"chain": "ethereum",
"value": "0x000000000000000000000000fcb19e6a322b27c06842a71e8c725399f049ae3a",
"signal": "Raw storage slot — inspect contract state directly, for audit & proxy-resolution agents.",
"source": "public JSON-RPC (eth_getStorageAt)",
"address": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
"license": "single-use",
"served_at": 1782881376356
}Schema · Response
{
"type": "json",
"example": {
"slot": "0x0",
"chain": "ethereum",
"value": "0x0000...0001",
"address": "0x..."
}
}Tags
x402
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