eth_estimateGas - Blast

Example code for the eth_estimateGas JSON-RPC method. Complete guide on how to use eth_estimateGas JSON-RPC in GetBlock Web3 documentation.

This method returns an estimate of the gas required to execute a transaction, without submitting it. On GIWA Sepolia the estimate covers L2 execution gas; the OP Stack L1 data fee is separate.

Parameters

Parameter	Type	Required	Description
transaction	object	Yes	Transaction call object
blockParameter	string	No	Block number in hex, or "latest", "pending"

Transaction Object

Field	Type	Required	Description
from	string	No	20-byte sender address
to	string	No	20-byte recipient/contract address (omit for deployment)
value	string	No	Value to send in wei (hex)
data	string	No	Encoded function call or deployment bytecode

Request

cURL

curl --location --request POST 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [{ "from": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "to": "0x4200000000000000000000000000000000000006", "value": "0xde0b6b3a7640000" }],
    "id": "getblock.io"
}'

Axios

example.js

const axios = require('axios');

const response = await axios.post('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/', {
    jsonrpc: '2.0',
    method: 'eth_estimateGas',
    params: [{ from: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', to: '0x4200000000000000000000000000000000000006', value: '0xde0b6b3a7640000' }],
    id: 'getblock.io'
}, {
    headers: { 'Content-Type': 'application/json' }
});

console.log(response.data.result);

Request

example.py

import requests

response = requests.post(
    'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'eth_estimateGas',
        'params': [{ 'from': '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', 'to': '0x4200000000000000000000000000000000000006', 'value': '0xde0b6b3a7640000' }],
        'id': 'getblock.io'
    }
)

print(response.json())

Rust

example.rs

use reqwest::Client;
use serde_json::{json, Value};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();

    let response = client
        .post("https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "eth_estimateGas",
            "params": [{ "from": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "to": "0x4200000000000000000000000000000000000006", "value": "0xde0b6b3a7640000" }],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

    println!("Result: {}", response["result"]);
    Ok(())
}

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x5208"
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	string	Hex-encoded estimated L2 gas units

Use Cases

• Gas Limits: Set a safe gas limit before signing a transaction

• Fee Preview: Multiply the estimate by gas price to preview execution cost

• Revert Detection: Catch a would-fail transaction before broadcast

• Deployment Sizing: Estimate gas for contract creation calldata

Error Handling

Error Code	Message	Description
-32602	Invalid params	Malformed transaction object
3	Execution reverted	The transaction would revert during estimation
-32000	Execution error	Insufficient funds or gas required exceeds allowance

Web3 Integration

Ethers.js

ethers-example.js

import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/');

const gas = await provider.estimateGas({ from: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', to: '0x4200000000000000000000000000000000000006', value: ethers.parseEther('1') });

Viem

viem-example.js

import { createPublicClient, http } from 'viem';

const client = createPublicClient({
  transport: http('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/')
});

const gas = await client.estimateGas({ account: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', to: '0x4200000000000000000000000000000000000006', value: parseEther('1') });