Estimate Gas for Transaction

POST

https://trx.nownodes.io/jsonrpc

Authorizations

ApiKeyAuthApiKeyAuth

api-key string

NOWNodes API key passed in the api-key header.

Simulates a transaction and returns an estimate of how much gas would be used.

Body

application/json

Request value.

jsonrpcstringrequired

JSON-RPC protocol version

methodstringrequired

The method name

paramsArray<object | string>required

The transaction call object and an optional block tag.

Show child attributes

Single array item value.

One of

fromstring

Address the transaction is sent from (optional)

tostringrequired

Destination address of the call

gasstring

Gas limit provided for execution (optional)

gasPricestring

Gas price in wei (optional)

valuestring

Amount of ETH to send, in hexadecimal wei (optional)

datastring

The compiled input data for the transaction (optional)

Optional block tag (e.g., "latest", "earliest", or a block number)

string

idintegerrequired

Request identifier

Response

200OK

HTTP 200 response for eth_estimateGas. The body contains either a successful result or a node-level error.

400Bad Request

Bad Request. The request is malformed or contains invalid parameters.

401Unauthorized

Unauthorized: API key is present but rejected by the NOWNodes gateway.

405Method Not Allowed

Method Not Allowed. Returned by the NOWNodes gateway for malformed or unsupported gateway-level requests.

422Unprocessable Entity

Missing API key. The NOWNodes gateway returns plain text for this error.

500Internal Server Error

Internal Server Error. The gateway or node failed while processing the request.

Estimate Gas for Transaction

curl -X POST 'https://trx.nownodes.io/jsonrpc' \
  -H 'Content-Type: application/json' \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [
      {
        "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
        "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
        "gas": "0x76c0",
        "gasPrice": "0x9184e72a000",
        "value": "0x0",
        "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
      }
    ],
    "id": 1
  }'

import { JsonRpcProvider } from "ethers";

const provider = new JsonRpcProvider("https://trx.nownodes.io/jsonrpc");
const result = await provider.send("eth_estimateGas", [
  {
    "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
    "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
    "gas": "0x76c0",
    "gasPrice": "0x9184e72a000",
    "value": "0x0",
    "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
  }
]);
console.log(result);

require 'eth'
require 'json'
require 'net/http'

uri = URI('https://trx.nownodes.io/jsonrpc')
request = Net::HTTP::Post.new(uri)
request['Content-Type'] = 'application/json'
request.body = '{
  "jsonrpc": "2.0",
  "method": "eth_estimateGas",
  "params": [
    {
      "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
      "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
      "gas": "0x76c0",
      "gasPrice": "0x9184e72a000",
      "value": "0x0",
      "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
    }
  ],
  "id": 1
}'

response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) do |http|
  http.request(request)
end

puts JSON.parse(response.body)

from web3 import Web3

w3 = Web3(Web3.HTTPProvider("https://trx.nownodes.io/jsonrpc"))
response = w3.provider.make_request("eth_estimateGas", [
  {
    "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
    "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
    "gas": "0x76c0",
    "gasPrice": "0x9184e72a000",
    "value": "0x0",
    "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
  }
])
print(response)

import { createPublicClient, http } from "viem";

const client = createPublicClient({
  transport: http("https://trx.nownodes.io/jsonrpc"),
});

const result = await client.request({
  method: "eth_estimateGas",
  params: [
  {
    "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
    "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
    "gas": "0x76c0",
    "gasPrice": "0x9184e72a000",
    "value": "0x0",
    "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
  }
],
});

console.log(result);

const endpoint = "https://trx.nownodes.io/jsonrpc";
const apiKey = "YOUR_API_KEY";

async function nownodesRequest(payload) {
  const response = await fetch(endpoint, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "api-key": apiKey,
    },
    body: JSON.stringify(payload),
  });

  return response.json();
}

const result = await nownodesRequest({ jsonrpc: "2.0", method: "eth_estimateGas", params: [
  {
    "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
    "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
    "gas": "0x76c0",
    "gasPrice": "0x9184e72a000",
    "value": "0x0",
    "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
  }
], id: 1 });
console.log(result);

const response = await fetch('https://trx.nownodes.io/jsonrpc', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
      "jsonrpc": "2.0",
      "method": "eth_estimateGas",
      "params": [
        {
          "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
          "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
          "gas": "0x76c0",
          "gasPrice": "0x9184e72a000",
          "value": "0x0",
          "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
        }
      ],
      "id": 1
    }),
});

const data = await response.json();

import requests

payload = {
  "jsonrpc": "2.0",
  "method": "eth_estimateGas",
  "params": [
    {
      "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
      "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
      "gas": "0x76c0",
      "gasPrice": "0x9184e72a000",
      "value": "0x0",
      "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
    }
  ],
  "id": 1
}

response = requests.post('https://trx.nownodes.io/jsonrpc', json=payload)
data = response.json()

require 'net/http'
require 'json'

uri = URI('https://trx.nownodes.io/jsonrpc')
request = Net::HTTP::Post.new(uri)
request['Content-Type'] = 'application/json'
request.body = '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [
      {
        "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
        "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
        "gas": "0x76c0",
        "gasPrice": "0x9184e72a000",
        "value": "0x0",
        "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
      }
    ],
    "id": 1
  }'

response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http| http.request(request) }
data = JSON.parse(response.body)

Request Body

{
  "jsonrpc": "2.0",
  "method": "eth_estimateGas",
  "params": [
    {
      "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
      "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
      "gas": "0x76c0",
      "gasPrice": "0x9184e72a000",
      "value": "0x0",
      "data": "0x70a08231000000000000000000000000a0df350d2637096571f7a701cbc1c5fd"
    }
  ],
  "id": 1
}

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x0"
}

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32602,
    "message": "invalid argument 0: invalid parameter for eth_estimateGas"
  }
}

{
  "code": 400,
  "message": "Bad Request"
}

Unknown API_key

Method Not Allowed

Missing API_key

{
  "code": 500,
  "message": "Internal Server Error"
}

Documentation

How to migrate to NOWNodes

Estimate Gas for Transaction

Authorizations

Body

Response