> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tenderly.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Simulations Quickstart

> Simulate your first transaction with tenderly_simulateTransaction over Node RPC, verifying behavior before sending it onchain in minutes.

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](/node-rpc/rpc-reference?network=ethereum-mainnet\&method=tenderly_simulateTransaction). Simulations allow you to precisely verify the transaction's behavior before sending it to the blockchain.

<Note>
  Simulation RPC is available both on [Node RPC](/node-rpc/rpc-reference?network=ethereum-mainnet\&method=tenderly_simulateTransaction) and [Virtual Environment RPCs](/virtual-environments/interact/simulate-transactions)
</Note>

## Get the RPC URL

Log into your [Tenderly account](https://dashboard.tenderly.co/register?redirectTo=gateways) 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](/simulations/single-simulations#simulate-via-api) instead.

```bash title="example" showLineNumbers theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
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**

```bash title="example" showLineNumbers theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
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",
        "value": "0x0",
        "data": "0xa9059cbb00000000000000000000000020a5814b73ef3537c6e099a0d45c798f4bd6e1d60000000000000000000000000000000000000000000000000000000000000001"
      },
      "latest"
    ]
  }'
```

## Explore use cases

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

## Where to go next

<Card title="Bundled simulations" href="" />

<Card title="Simulate via SDK" href="" />