Simulate Transactions

Transaction simulations are supported on Virtual Environments. You can simulate transactions form the Dashboard UI or programmatically using RPC.

Simulator UI

Simulation RPC

Bundle Simulation RPC

Simulation API on Virtual Environments

Simulate from the Dashboard

To simulate a transaction from the Dashboard, go to Virtual Environments and click Simulate from the left-hand menu. Simulated transactions are visible only within the Virtual Environment dashboard and won’t be visible in the Public Explorer. You can use the Simulator in the following ways:

Debug smart contracts errors, using Edit Source to check your bugfix.
Call contracts to get a sense of states without persisting transactions to the network.
Set up desired contract states using State Overrides, to evaluate the execution under conditions that aren’t and shouldn’t be present on the chain.
Build proof of concept transactions to validate testing scenarios.

Simulate via RPC

Transactions on Virtual Environments can also be simulated using our the RPC methods tenderly_simulate and tenderly_simulateBundle.

We recommend integrating the Simulation RPC, but it’s possible to use Simulation REST API.

The example code below runs a simulation that uses state overrides to mint DAI.

Sender address: 0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2.
DAI contract address: 0x6b175474e89094c44da98b954eedeac495271d0f
State override arguments: DAI(0x6b175474e89094c44da98b954eedeac495271d0f).wards[0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2] = 1

Explore this guide to learn more about simulating with state overrides.

showLineNumbers

# simulate DAI minting by 0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2
# 0xf1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1 gets the minted DAI
# Simulated on the latest block

VIRTUAL_TESTNET_RPC=RPC_LINK_HERE

curl $VIRTUAL_TESTNET_RPC \
-X POST \
-H "Content-Type: application/json" \
-d \
'{
  "id":0,
  "jsonrpc":"2.0",
  "method":"tenderly_simulateTransaction",
  "params":[
    {
      "from":"0xe2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2e2",
      "to":"0x6b175474e89094c44da98b954eedeac495271d0f",
      "gas":"0x7a1200",
      "data":"0x40c10f19000000000000000000000000f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f1f10000000000000000000000000000000000000000000000001bc16d674ec80000"
    },
    "latest",
    {
      "0x6b175474e89094c44da98b954eedeac495271d0f":{
        "stateDiff":{
          "0xedd7d04419e9c48ceb6055956cbb4e2091ae310313a4d1fa7cbcfe7561616e03":"0x0000000000000000000000000000000000000000000000000000000000000001"
        },
        "balance": "0xFFFFFF"
      }
    }
  ]
}'