Simulations Quickstart

This quickstart guide demonstrates how to simulate a single transaction on the Node RPC using a custom RPC method tenderly_simulateTransaction. See RPC simulation reference. Simulations allow you to precisely verify the transaction’s behavior before sending it to the blockchain.

Get the RPC URL

Log into your Tenderly account and from the left-hand menu click on Node.

Copy the RPC URL of your preferred network. If your network is not supported on the Node, simulate via API instead.

https://mainnet.gateway.tenderly.co/${TENDERLY_NODE_ACCESS_KEY}

The access key is automatically appended to the end of the RPC URL.

Send the request

Make a POST request to the RPC URL.

Your request must include:

• The RPC URL with your access key.
• Call to the RPC method tenderly_simulateTransaction.
• Transaction parameters such as from, to, gas, gas price, value, and data.

Example cURL request

curl https://mainnet.gateway.tenderly.co/$TENDERLY_NODE_ACCESS_KEY \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "id": 0,
    "jsonrpc": "2.0",
    "method": "tenderly_simulateTransaction",
    "params": [
      {
        "from": "0xd8da6bf26964af9d7eed9e03e53415d37aa96045",
        "to": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
        "gas": "0x0",
        "gasPrice": "0x0",
        "value": "0x0",
        "data": "0xa9059cbb00000000000000000000000020a5814b73ef3537c6e099a0d45c798f4bd6e1d60000000000000000000000000000000000000000000000000000000000000001"
      },
      "latest"
    ]
  }'

Explore use cases

• Asset and balance changes: Get exact dollar values for all balance and asset changes that will happen.
• Gas estimation: Accurately predict the gas costs before sending the transaction.
• State overrides: Modify blockchain conditions like timestamps and contract data to test different scenarios.
• Preview transaction outcomes: Identify and fix issues that could cause transactions to fail.

Where to go next