zks_estimateGasL1ToL2 - zkSync

Example code for the zks_estimateGasL1ToL2 JSON-RPC method. Сomplete guide on how to use zks_estimateGasL1ToL2 JSON-RPC in GetBlock.io Web3 documentation.

Estimates the gas required for an L1 to L2 transaction. Use this when preparing L1 contracts that send messages or assets into zkSync Era.

Parameters

Parameter	Type	Required	Description
callRequest	object	Yes	Transaction-shaped object with from, to, data, and optional fields

Request Example

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": "zks_estimateGasL1ToL2",
    "params": [
        {
            "from": "0x1111111111111111111111111111111111111111",
            "to": "0x2222222222222222222222222222222222222222",
            "data": "0xffffffff"
        }
    ],
    "id": "getblock.io"
}'

JavaScript (Axios)

import axios from 'axios';

const data = JSON.stringify({
    "jsonrpc": "2.0",
    "method": "zks_estimateGasL1ToL2",
    "params": [
        {
            "from": "0x1111111111111111111111111111111111111111",
            "to": "0x2222222222222222222222222222222222222222",
            "data": "0xffffffff"
        }
    ],
    "id": "getblock.io"
});

const config = {
    method: 'post',
    url: 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers: {
        'Content-Type': 'application/json'
    },
    data: data
};

axios(config)
    .then(response => console.log(JSON.stringify(response.data, null, 2)))
    .catch(error => console.log(error));

Python (Requests)

import requests
import json

url = "https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/"

payload = json.dumps({
    "jsonrpc": "2.0",
    "method": "zks_estimateGasL1ToL2",
    "params": [
        {
            "from": "0x1111111111111111111111111111111111111111",
            "to": "0x2222222222222222222222222222222222222222",
            "data": "0xffffffff"
        }
    ],
    "id": "getblock.io"
})

headers = {
    'Content-Type': 'application/json'
}

response = requests.post(url, headers=headers, data=payload)
print(response.text)

Rust (Reqwest)

use reqwest::Client;
use serde_json::json;

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

    let payload = json!({
        "jsonrpc": "2.0",
        "method": "zks_estimateGasL1ToL2",
        "params": [
                {
                        "from": "0x1111111111111111111111111111111111111111",
                        "to": "0x2222222222222222222222222222222222222222",
                        "data": "0xffffffff"
                }
        ],
        "id": "getblock.io"
});

    let response = client
        .post("https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&payload)
        .send()
        .await?;

    let result: serde_json::Value = response.json().await?;
    println!("{:#?}", result);

    Ok(())
}

Response Example

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x25f64db"
}

Response Parameters

Field	Type	Description
result	string	Estimated gas amount in hexadecimal (32 bytes)

Use Cases

• Bridging and L1→L2 message senders

• Setting correct gas budgets in L1 deposit contracts

• Bridge UX showing accurate cost estimates

Error Handling

Status Code	Error Message	Cause
403	Forbidden	Missing or invalid <ACCESS-TOKEN>
-32602	Invalid params	Request parameters are missing or malformed
429	Too Many Requests	Rate limit exceeded for your plan

SDK Integration

zksync-ethers (JavaScript)

import { Provider } from 'zksync-ethers';

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

// zksync-ethers exposes both standard Ethereum methods and zks_* methods
// through typed accessors. For raw access:
const result = await provider.send('zks_estimateGasL1ToL2', [{"from": "0x1111111111111111111111111111111111111111", "to": "0x2222222222222222222222222222222222222222", "data": "0xffffffff"}]);
console.log(result);

zksync2-python (Python)

from zksync2.module.module_builder import ZkSyncBuilder

zk_web3 = ZkSyncBuilder.build('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/')

// zksync2-python exposes the JSON-RPC layer directly.
result = zk_web3.zksync._zks_endpoints if 'zks_estimateGasL1ToL2'.startswith('zks_') else None
# Or call any method generically:
result = zk_web3.provider.make_request('zks_estimateGasL1ToL2', [{"from": "0x1111111111111111111111111111111111111111", "to": "0x2222222222222222222222222222222222222222", "data": "0xffffffff"}])
print(result)