Simulate Transactions on TestNets

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

Simulate from the Dashboard

To simulate a transaction from the Dashboard, go to Virtual TestNets and click Simulate from the left-hand menu. Simulated transactions are visible only within the TestNet 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 TestNets can also be simulated using our the RPC methods tenderly_simulate and tenderly_simulateBundle.

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.

# 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"
      }
    }
  ]
}'

Simulate transactions via client libraries

To simulate transactions via Ethers and Viem, check out the following example: