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eth_getStorageAt

Returns the value from a storage position at a given address.

For Growth and Custom service plans

This JSON-RPC method allows a request to be forwarded to a partner service provider if Infura should experience a service issue or outage. See Failover protection and Enable API request forwarding for complete details.

If you would like failover protection but don't qualify under your current plan, then either self-upgrade to the Growth plan or contact a sales representative to upgrade to a Custom plan.

Parameters​

  • address: [Required] A string representing the address (20 bytes) of the storage.
  • storage position: [Required] A hexadecimal code of the position in the storage.
  • block parameter: [Required] A hexadecimal block number, or one of the string tags latest, earliest, pending, safe, or finalized. See the default block parameter.

Returns​

storage value: A hexadecimal equivalent of the integer indicating the value of the storage position at the provided address.

Example​

Replace YOUR-API-KEY with an API key from your Infura dashboard.

Request​

curl https://polygon-mainnet.infura.io/v3/YOUR-API-KEY \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getStorageAt","params": ["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9", "0x65a8db"],"id":1}'

Response​

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x0000000000000000000000000000000000000000000000000000000000000000"
}

Additional notes​

Calculating the correct position depends on the storage to retrieve. Consider the following contract deployed at 0x295a70b2de5e3953354a6a8344e616ed314d7251 by address 0x391694e7e0b0cce554cb130d723a9d27458f9298,

contract Storage {
    uint pos0;
    mapping(address => uint) pos1;

    function Storage() {
        pos0 = 1234;
        pos1[msg.sender] = 5678;
    }
}

Retrieving the value of pos0 is straight forward:

curl https://mainnet.infura.io/v3/YOUR-API-KEY \
    -X POST \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc":"2.0", "method": "eth_getStorageAt", "params": ["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x0", "0x65a8db"], "id": 1}'
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x00000000000000000000000000000000000000000000000000000000000004d2"
}

Retrieving an element of the map is harder. The position of an element in the map is calculated with:

keccak(LeftPad32(key, 0), LeftPad32(map position, 0))

This means to retrieve the storage on pos1["0x391694e7e0b0cce554cb130d723a9d27458f9298"] we need to calculate the position with:

keccak(
  decodeHex(
    "000000000000000000000000391694e7e0b0cce554cb130d723a9d27458f9298" +
      "0000000000000000000000000000000000000000000000000000000000000001",
  ),
);

The geth console which comes with the web3 library can be used to make the calculation:

> var key = "000000000000000000000000391694e7e0b0cce554cb130d723a9d27458f9298" + "0000000000000000000000000000000000000000000000000000000000000001"
undefined
> web3.sha3(key, {"encoding": "hex"})
"0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9"

Now to fetch the storage:

curl https://mainnet.infura.io/v3/YOUR-PROJECT-ID \
    -X POST \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc":"2.0", "method": "eth_getStorageAt", "params": ["0x295a70b2de5e3953354a6a8344e616ed314d7251", "0x6661e9d6d8b923d5bbaab1b96e1dd51ff6ea2a93520fdc9eb75d059238b8c5e9", "0x65a8db"], "id": 1}'
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x000000000000000000000000000000000000000000000000000000000000162e"
}
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