The eth_call method executes a new message call immediately without creating a transaction on the blockchain. This method is perfect for reading data from smart contracts without spending gas or modifying the blockchain state, making it one of the most frequently used methods for DApp development.

Use Cases

Reading token balances from ERC20 contracts
Querying contract state variables and mappings
Checking transaction validity before submission
Debugging smart contract functions
Testing contract behavior with different inputs
Simulating complex transaction outcomes
Fetching price data from DEX contracts
Verifying access rights before attempting state changes

Method Details

This method allows interaction with deployed smart contracts in a read-only manner with optional state overrides. The state overrides feature is particularly useful for testing "what-if" scenarios.

パラメータ:

transactionobject[required]

The transaction call object which contains the following fields:

fromstring

The address from which the transaction is sent

tostring[required]

The address to which the transaction is addressed

gasinteger

The integer of gas provided for the transaction execution

gasPriceinteger

The integer of gasPrice used for each paid gas encoded as hexadecimal

valueinteger

The integer of value sent with this transaction encoded as hexadecimal

datastring

The hash of the method signature and encoded parameters. For more information, see the Contract ABI description in the Solidity documentation

blockNumberstring[required]

The block number in hexadecimal format or one of the string tags: latest, earliest, pending, safe or finalized (safe and finalized tags are only supported on Ethereum, Gnosis, Arbitrum, Arbitrum Nova and Avalanche C-chain)

stateOverrideobject

The State Override Set option allows you to change the state of a contract before executing the call

balancestring

The fake balance to set for the account before executing the call

noncestring

The fake nonce to set for the account before executing the call

codestring

The fake EVM bytecode to inject into the account before executing the call

stateobject

The fake key-value mapping to override all slots in the account storage before executing the call

stateDiffinteger

The fake key-value mapping to override individual slots in the account storage before executing the call

返り値:

resultstring

The return value of the executed contract method

Response Example

{
	"jsonrpc": "2.0",
	"id": 1,
	"result": "0x00000000000000000000000000000000000000000000015af1d78b58c4000000"
}

Common ERC20 Function Calls

One of the most common uses of eth_call is to check ERC20 token balances. The data field typically contains the function signature followed by the parameters:

balanceOf(address): 0x70a08231 + padded address
decimals(): 0x313ce567
symbol(): 0x95d89b41
totalSupply(): 0x18160ddd

The response will need to be decoded according to the expected return type.