trace_call

Traces a call without creating a transaction on Optimism, returning the trace output.

Archive Node Required

This method requires an archive node. It is not available on full nodes.

Use Cases

• Call simulation - Preview internal calls before sending a transaction
• Contract interaction analysis - Understand how contracts interact
• Gas estimation - Analyze gas usage patterns for cross-chain DeFi, Superchain-interoperable dApps, and public goods funding recipients

Parameters

Parameter	Type	Required	Description
callObject	Object	Yes	Transaction call object (from, to, gas, value, data)
traceTypes	Array	Yes	Trace types: ["trace"], ["vmTrace"], ["stateDiff"], or combinations
blockNumber	QUANTITY|TAG	No	Block number or tag (default: latest)

Request

{
  "jsonrpc": "2.0",
  "method": "trace_call",
  "params": [
    {
      "to": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
      "data": "0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
    },
    ["trace"],
    "latest"
  ],
  "id": 1
}

Code Examples

cURL

curl -X POST https://api-optimism-mainnet-archive.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "trace_call",
    "params": [
      {"to": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "data": "0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045"},
      ["trace"],
      "latest"
    ],
    "id": 1
  }'

JavaScript

import { JsonRpcProvider } from 'ethers';

const provider = new JsonRpcProvider('https://api-optimism-mainnet-archive.n.dwellir.com/YOUR_API_KEY');

const result = await provider.send('trace_call', [
  {
    to: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    data: '0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045'
  },
  ['trace'],
  'latest'
]);
console.log('Trace output:', result.trace);
console.log('VM trace:', result.vmTrace);

Python

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('https://api-optimism-mainnet-archive.n.dwellir.com/YOUR_API_KEY'))

result = w3.provider.make_request('trace_call', [
    {
        'to': '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
        'data': '0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045'
    },
    ['trace'],
    'latest'
])
print(f'Trace: {result["result"]["trace"]}')

Related Methods

• trace_filter - Filter traces by criteria
• eth_call - Execute call without trace
• trace_transaction - Trace a specific transaction