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EVM Storage Slot Hash Calculator
x402
EVM Storage Slot Hash Calculator is a paid API for AI agents from bot-bazaar.fly.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-31).
Computes the exact EVM storage slot hash keccak256(abi.encode(key, slot)) for a Solidity mapping entry given a mapping key.
Price / call$0.01
Success—
StatusUnknown
How this service works
Compute the exact EVM storage slot hash keccak256(abi.encode(key, slot)) for a Solidity mapping entry.
Output
Returns the computed keccak256(abi.encode(key, slot)) hash representing the exact EVM storage slot where the mapping entry for the given key is stored, expressed as a 32-byte hex string.
Example use cases
Inspect live contract storage value
“I need the exact storage slot hash for address 0xDEADBEEF000000000000000000000000deadbeef at slot 0 in a Solidity mapping so I can call eth_getStorageAt and read the raw value from the contract.”
Debug Solidity mapping storage layout
“My smart contract has a balances mapping at slot 3 — can you compute the storage slot hash for key 0x1111111111111111111111111111111111111111 so I can verify the value is stored at the right location?”
Automate storage proof verification
“I'm building a storage proof and need the keccak256 abi.encode hash for mapping key 0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa at slot index 5 — what's the resulting storage slot?”
Technical details
Endpoint
GEThttps://bot-bazaar.fly.dev/v1/x402/storage-slot-calc?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to deterministically compute the EVM storage slot for a Solidity mapping entry (keccak256(abi.encode(key, slot))) without running a local EVM or writing custom code. It is ideal for automating eth_getStorageAt lookups, building storage proofs, or debugging smart contract storage layouts.
Side effects
- Missing or malformed mapping_key parameter returns an error
- Invalid hex format for key (not a valid address or 32-byte hex) causes a parsing error
- Missing slot index may result in a default or error depending on implementation
- Network or server errors from the fly.dev host may return 5xx responses
- Payment failure or invalid x402 payment header returns 402 Payment Required
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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