debug_traceCall

Traces a call without creating a transaction on Optimism.

Archive Node Required

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

Use Cases

• Transaction simulation - Debug before sending
• Gas analysis - Analyze gas usage per opcode
• Contract debugging - Step through execution for cross-chain DeFi, Superchain-interoperable dApps, and public goods funding recipients

Parameters

Parameter	Type	Required	Description
call	Object	Yes	Call object (same as eth_call)
blockNumber	QUANTITY|TAG	Yes	Block number or tag
tracerConfig	Object	No	Tracer configuration

Request

{
  "jsonrpc": "2.0",
  "method": "debug_traceCall",
  "params": [
    {
      "to": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
      "data": "0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
    },
    "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": "debug_traceCall",
    "params": [
      {"to": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "data": "0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045"},
      "latest",
      {"tracer": "callTracer"}
    ],
    "id": 1
  }'

JavaScript

import { JsonRpcProvider } from 'ethers';

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

const trace = await provider.send('debug_traceCall', [
  { to: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045', data: '0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045' },
  'latest',
  { tracer: 'callTracer' }
]);
console.log('Trace:', trace);

Related Methods

• eth_call - Execute call without trace
• debug_traceTransaction - Trace actual transaction