eth_call

Executes a new message call immediately without creating a transaction on the block chain.

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This is one of the most commonly used API calls. It is used to read from the blockchain which includes executing smart contracts but does not publish anything to the blockchain. This call does not consume any Ether.

We can call any function of a smart contract using the eth_call method and it returns us any data that the function returns (in hex format). For read-only functions, it returns what the read-only function returns. For functions that change the state of the contract, it executes that transaction locally and returns any data returned by the function.

Calling the read-only function is a common use case because all read-only functions return something that we can read using this method.

Use cases for eth_call

eth_call is used to call read-only functions of a smart contract. For example, calling the balanceOf function of an ERC20 token contract.

🚧

Starting from Geth 1.9.13, eth_callwill check the balance of the sender (to make sure that the sender has enough gas to complete the request) before executing the call when one of the following conditions is true:

  1. the gas_price parameter is populated, or
  2. the contract function being called (i.e. in data modifies blockchain state)\

In these two cases, even though the eth_call requests don't consume any gas, the from address must have enough gas to execute the call as if it were a write transaction because eth_call is being used to simulate the transaction.

Parameters

  • Object - The transaction call object
    • from: DATA, 20 Bytes - (optional) The address the transaction is sent from.
    • to: DATA, 20 Bytes - The address the transaction is directed to.
    • gas: QUANTITY - (optional) Integer of the gas provided for the transaction execution. eth_call consumes zero gas, but this parameter may be needed by some executions. NOTE: this parameter has a cap of 550 million gas per request. Reach out to us at [email protected] if you want to increase this limit!
    • gasPrice: QUANTITY - (optional) Integer of the gasPrice used for each paid gas.
    • value: QUANTITY - (optional) Integer of the value sent with this transaction
    • data: DATA - (optional) Hash of the method signature and encoded parameters. For details see Ethereum Contract ABI
  • QUANTITY|TAG - integer block number, or the string "latest", "earliest" or "pending" (see the default block parameter), OR the blockHash (in accordance with EIP-1898) NOTE: the parameter is an object instead of a string and should be specified as: {"blockHash": "0x<some-hash>"}. Learn more here.

❗️

Note

eth_call has a timeout restriction at the node level. Batching multiple eth_call together on-chain using pre-deployed smart contracts might result in unexpected timeouts that cause none of your calls to complete. Instead, consider serializing these calls, or using smaller batches if they fail with a node error code.

params: [
    {
        "from": "0xb60e8dd61c5d32be8058bb8eb970870f07233155",
        "to": "0xd46e8dd67c5d32be8058bb8eb970870f07244567",
        "gas": "0x76c0",
        "gasPrice": "0x9184e72a000",
        "value": "0x9184e72a",
        "data": "0xd46e8dd67c5d32be8d46e8dd67c5d32be8058bb8eb970870f072445675058bb8eb970870f072445675"
    }, 
    "latest"
]

Returns

DATA - the return value of the executed contract.

Example

Request

// Setup: npm install alchemy-sdk
// Github: https://github.com/alchemyplatform/alchemy-sdk-js
import { Network, Alchemy } from "alchemy-sdk";

// Optional config object, but defaults to demo api-key and eth-mainnet.
const settings = {
  apiKey: "demo", // Replace with your Alchemy API Key.
  network: Network.ETH_MAINNET, // Replace with your network.
};
const alchemy = new Alchemy(settings);

// Make a sample eth_call
alchemy.core
  .call({
    to: "0x4976fb03C32e5B8cfe2b6cCB31c09Ba78EBaBa41",
    gas: "0x76c0",
    gasPrice: "0x9184e72a000",
    data: "0x3b3b57debf074faa138b72c65adbdcfb329847e4f2c04bde7f7dd7fcad5a52d2f395a558",
  })
  .then(console.log);
// Installation instructions: https://docs.ethers.io/v5/getting-started/#installing

async function main() {
   const { ethers } = require("ethers");
   
    // Replace with your Alchemy API key:
    const apiKey = "demo";

    // Initialize an ethers instance
    const provider = new ethers.providers.AlchemyProvider("homestead", apiKey);

    // Query the blockchain (replace example parameters)
    const data = await provider.call(
        {
            "from": "0xb60e8dd61c5d32be8058bb8eb970870f07233155",
            "to": "0xd46e8dd67c5d32be8058bb8eb970870f07244567",
            "gas": "0x76c0",
            "gasPrice": "0x9184e72a000",
            "value": "0x9184e72a",
            "data": "0xd46e8dd67c5d32be8d46e8dd67c5d32be8058bb8eb970870f072445675058bb8eb970870f072445675"
        }, 
        "latest"
    ); 
    
    // Print the output to console
    console.log(data);
   }

main()
# Installation Instructions: https://web3py.readthedocs.io/en/latest/quickstart.html#installation

from web3 import Web3, HTTPProvider

#Replace with your Alchemy API key:
apiKey = "demo"

# Initialize a Web3.py instance
web3 = Web3(Web3.HTTPProvider('https://eth-mainnet.g.alchemy.com/v2/'+apiKey))

# Query the blockchain (replace example parameters)
data = web3.eth.call({
        'value': 0, 
        'gas': 21736, 
        'maxFeePerGas': 2000000000, 
        'maxPriorityFeePerGas': 1000000000, 
        'to': '0xc305c90',
        'data': '0x477a5c98'
        }) 

# Print the output to console
print(data)
curl https://eth-mainnet.g.alchemy.com/v2/your-api-key \
-X POST \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","method":"eth_call","params":[{"from": "0xb60e8dd61c5d32be8058bb8eb970870f07233155","to": "0xd46e8dd67c5d32be8058bb8eb970870f07244567","gas": "0x76c0","gasPrice": "0x9184e72a000","value": "0x9184e72a","data": "0xd46e8dd67c5d32be8d46e8dd67c5d32be8058bb8eb970870f072445675058bb8eb970870f072445675"}, "latest"],"id":1}'
URL: https://eth-mainnet.g.alchemy.com/v2/your-api-key
RequestType: POST
Body: 
{
    "jsonrpc":"2.0",
    "method":"eth_call",
    "params":[{"from": "0xb60e8dd61c5d32be8058bb8eb970870f07233155","to": "0xd46e8dd67c5d32be8058bb8eb970870f07244567","gas": "0x76c0","gasPrice": "0x9184e72a000","value": "0x9184e72a","data": "0xd46e8dd67c5d32be8d46e8dd67c5d32be8058bb8eb970870f072445675058bb8eb970870f072445675"}, "latest"],
    "id":1
}

Result

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