eth_estimateGas

eth_estimateGas runs a transaction against the current state and returns a hex-encoded estimate of the gas it would consume, without submitting the transaction or changing any state. Use it to set the gas limit before signing and sending a transaction with eth_sendRawTransaction, or to check whether a call would revert.

The estimate is an upper bound derived from a binary search over a simulated execution; it is not guaranteed to equal the gas the transaction actually uses once mined. State can change between the estimate and inclusion (storage slots, balances, nonces), and some contracts branch on gasleft(), so the real gas used may be lower — and in rare cases a transaction that estimated cleanly can still revert. A common practice is to add a small safety margin (for example 10–20%) on top of the returned value when setting the transaction's gas limit.

If the simulated execution reverts, the call returns an error rather than a gas value; the revert reason, when available, is surfaced in the error data.

Positional params array: [transaction, blockTag?].

Response fields

Errors follow the shared JSON-RPC error envelope — see Errors for the full structure and handling guidance.

JavaScript (fetch)

const res = await fetch("https://api.triport.io/v1/ethereum", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.TRIPORT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    jsonrpc: "2.0",
    id: 1,
    method: "eth_estimateGas",
    params: [
      {
        from: "0xb60e8dd61c5d32be8058bb8eb970870f07233155",
        to: "0xd46e8dd67c5d32be8058bb8eb970870f07244567",
        value: "0x9184e72a",
      },
    ],
  }),
});


const { result } = await res.json();
const gas = parseInt(result, 16); // 21000

TypeScript SDK (@triport/sdk)

import { Triport } from "@triport/sdk";


const triport = new Triport({ apiKey: process.env.TRIPORT_API_KEY! });


const gasHex = await triport.ethereum.estimateGas({
  from: "0xb60e8dd61c5d32be8058bb8eb970870f07233155",
  to: "0xd46e8dd67c5d32be8058bb8eb970870f07244567",
  value: "0x9184e72a",
});


const gas = parseInt(gasHex, 16); // 21000

Python (triport-sdk)

import os
from triport import Triport


triport = Triport(api_key=os.environ["TRIPORT_API_KEY"])


gas_hex = triport.ethereum.estimate_gas(
    {
        "from": "0xb60e8dd61c5d32be8058bb8eb970870f07233155",
        "to": "0xd46e8dd67c5d32be8058bb8eb970870f07244567",
        "value": "0x9184e72a",
    }
)


gas = int(gas_hex, 16)  # 21000

• The returned value is hex-encoded — decode with parseInt(result, 16) (JS) or int(result, 16) (Python) before use.
• Add a safety margin (≈10–20%) when applying the estimate as a transaction's gas limit; the actual gas used at inclusion time can differ from the estimate.
• A reverting simulation returns an error, not a gas figure — use this to detect calls that would fail before paying to broadcast them.
• Related methods: eth_call (read-only simulation returning result data), eth_gasPrice and eth_feeHistory (current pricing), and eth_sendRawTransaction (broadcast a signed transaction).