Rust SDK - Simulating Transactions

Simulating transactions allows you to preview the cost and effect of submitting a transaction without paying fees. You can use this to estimate fees, test a transaction, or to check what the output might be.

To simulate a transaction, pass in an account and a payload:

use aptos_sdk::{Aptos, AptosConfig, account::Ed25519Account, transaction::EntryFunction};

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let aptos = Aptos::new(AptosConfig::devnet())?;
    let sender = Ed25519Account::generate();
    let recipient = Ed25519Account::generate();

    aptos
        .fund_account(sender.address(), 1_000_000_000)
        .await?;

    let payload = EntryFunction::apt_transfer(recipient.address(), 10_000_000)?;
    let result = aptos.simulate(&sender, payload.into()).await?;

    println!("Success: {}", result.success());
    println!("Gas used: {}", result.gas_used());
    println!("Gas unit price: {}", result.gas_unit_price());
    println!("VM status: {}", result.vm_status());

    Ok(())
}

You can also estimate gas with a safety buffer, or simulate a signed transaction:

let estimated_gas = aptos.estimate_gas(&sender, payload.clone().into()).await?;
let signed = aptos_sdk::transaction::builder::sign_transaction(&raw_txn, &sender)?;
let result = aptos.simulate_signed(&signed).await?;

Look here to see the full example of how to build, simulate, and submit a transaction.

You can also learn how to simulate more advanced transactions by looking at the following guides:

• Sponsored Transactions
• Multi-Agent Transactions