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eth_getStorageAt
Returns the value from a storage position at a given address, or in other words, returns the state of the contract's storage, which may not be exposed via the contract's methods.

Parameters

    DATA, 20 Bytes - address of the storage.
    QUANTITY - integer of the position in the storage.
    QUANTITY|TAG - integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.

Returns

    DATA - the value at this storage position.

Example

Calculating the correct position depends on the storage to retrieve. Consider the following contract deployed at 0x295a70b2de5e3953354a6a8344e616ed314d7251 by address 0x391694e7e0b0cce554cb130d723a9d27458f9298.
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contract Storage {
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uint pos0;
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mapping(address => uint) pos1;
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​
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function Storage() {
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pos0 = 1234;
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pos1[msg.sender] = 5678;
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}
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}
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Retrieving the value of pos0 is straight forward:
​Request​
Curl
Postman
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curl https://eth-mainnet.alchemyapi.io/v2/your-api-key \
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-X POST \
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-H "Content-Type: application/json" \
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-d '{"jsonrpc":"2.0", "method": "eth_getStorageAt", "params": ["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x0", "latest"], "id": 1}'
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URL: https://eth-mainnet.alchemyapi.io/v2/your-api-key
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RequestType: POST
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Body:
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{
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"jsonrpc":"2.0",
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"method":"eth_getStorageAt",
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"params":["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x0", "latest"],
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"id":1
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}
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Result
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{
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"jsonrpc":"2.0",
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"id":1,
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"result":"0x00000000000000000000000000000000000000000000000000000000000004d2"
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}
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Retrieving an element of the map is harder. The position of an element in the map is calculated with:
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keccack(LeftPad32(key, 0), LeftPad32(map position, 0))
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This means to retrieve the storage on pos1[β€œ0x391694e7e0b0cce554cb130d723a9d27458f9298”] we need to calculate the position with:
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keccak(decodeHex("000000000000000000000000391694e7e0b0cce554cb130d723a9d27458f9298" + "0000000000000000000000000000000000000000000000000000000000000001"))
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The geth console which comes with the web3 library can be used to make the calculation:
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> var key = "000000000000000000000000391694e7e0b0cce554cb130d723a9d27458f9298" + "0000000000000000000000000000000000000000000000000000000000000001"
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undefined
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> web3.sha3(key, {"encoding": "hex"})
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"0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9"
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Now to fetch the storage:
​Request​
Curl
Postman
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curl https://eth-mainnet.alchemyapi.io/v2/your-api-key \
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-X POST \
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-H "Content-Type: application/json" \
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-d '{"jsonrpc":"2.0", "method": "eth_getStorageAt", "params": ["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9", "latest"], "id": 1}'
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URL: https://eth-mainnet.alchemyapi.io/v2/your-api-key
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RequestType: POST
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Body:
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{
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"jsonrpc":"2.0",
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"method":"eth_getStorageAt",
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"params":["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9", "latest"],
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"id":1
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}
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Result
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{
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"jsonrpc":"2.0",
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"id":1,
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"result":"0x000000000000000000000000000000000000000000000000000000000000162e"
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}
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Last modified 2mo ago
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