Precise Gas Estimation Using Simulation API
The Simulation API allows you to simulate transactions and obtain the estimated gas usage needed to successfully execute the transactions.
Set estimate_gas: true in the request to get gas estimates.
Note: you can get 100% accurate gas estimates using the tenderly_estimateGas and tenderly_estimateGasBundle RPC methods.
Example
Make sure to store the access key securely in a .env file.
example.ts
import axios from 'axios';
import * as dotenv from 'dotenv';
dotenv.config();
const { TENDERLY_ACCOUNT_SLUG, TENDERLY_PROJECT_SLUG, TENDERLY_ACCESS_KEY } = process.env;
const simulateTransaction = async () => {
const { data } = await axios.post(
`https://api.tenderly.co/api/v1/account/${TENDERLY_ACCOUNT_SLUG}/project/${TENDERLY_PROJECT_SLUG}/simulate`,
{
// Simulation Configuration
save: true,
save_if_fails: false,
estimate_gas: true,
simulation_type: 'quick',
network_id: '1',
// Standard EVM Transaction object (sample values)
from: '0xdc6bdc37b2714ee601734cf55a05625c9e512461',
to: '0x6b175474e89094c44da98b954eedeac495271d0f',
input:
'0x095ea7b3000000000000000000000000f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1000000000000000000000000000000000000000000000000000000000000012b',
gas: 8000000,
gas_price: 0,
value: 0,
},
{
headers: {
'X-Access-Key': TENDERLY_ACCESS_KEY as string,
},
},
);
console.log({ data });
};
simulateTransaction();This calculates the maximum gas needed for the transaction. After a successful simulation, check the gas_used field in the transaction structure.
Result
example.json
"transaction": {
...
"gas": 8000000,
"gas_price": 0,
"gas_fee_cap": 0,
"gas_tip_cap": 0,
"cumulative_gas_used": 0,
"gas_used": 51534, // Gas estimates
"effective_gas_price": 0,
...
}