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POST
trace_call
curl --request POST \
  --url https://tempo-moderato.core.chainstack.com/a25a421add2280d53fdbc23417055501/ \
  --header 'Content-Type: application/json' \
  --data '
{
  "jsonrpc": "2.0",
  "method": "trace_call",
  "params": [
    {
      "to": "0x20c0000000000000000000000000000000000000",
      "data": "0x70a082310000000000000000000000009729187d9e8bbefa8295f39f5634ca454dd9d294"
    },
    [
      "trace"
    ],
    "latest"
  ],
  "id": 1
}
'
{
  "jsonrpc": "<string>",
  "id": 123,
  "result": {}
}
Tempo API method that traces a call without creating a transaction. This provides detailed execution traces using the Parity/OpenEthereum trace format.
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​
Parameters

  • callObject — the call object:
    • from — (optional) sender address
    • to — recipient address
    • gas — (optional) gas limit
    • gasPrice — (optional) gas price
    • value — (optional) value to send
    • data — (optional) call data
  • traceTypes — array of trace types to include:
    • trace — basic execution trace
    • vmTrace — full VM execution trace
    • stateDiff — state changes
  • blockParameter — the block number (hex) or tag (latest, earliest, pending)

​
Response

  • result — the trace result object:
    • output — return data from the call
    • trace — array of trace objects (if requested)
    • vmTrace — VM execution trace (if requested)
    • stateDiff — state differences (if requested)

​
trace_call code examples

The following example traces a balanceOf call on the pathUSD token: 
const ethers = require('ethers');
const NODE_URL = "CHAINSTACK_NODE_URL";
const provider = new ethers.JsonRpcProvider(NODE_URL);

// pathUSD token address
const PATHUSD = "0x20c0000000000000000000000000000000000000";
const TARGET_ADDRESS = "0x9729187D9E8Bbefa8295F39f5634cA454dd9d294";

// Encode balanceOf(address)
const iface = new ethers.Interface(["function balanceOf(address) view returns (uint256)"]);
const data = iface.encodeFunctionData("balanceOf", [TARGET_ADDRESS]);

const traceCall = async () => {
    const result = await provider.send("trace_call", [
      {
        to: PATHUSD,
        data: data
      },
      ["trace", "stateDiff"],
      "latest"
    ]);

    console.log("Output:", result.output);
    console.log("Traces:", result.trace.length);

    if (result.stateDiff) {
      console.log("State changes:", Object.keys(result.stateDiff).length, "addresses affected");
    }
  };

traceCall();

Body

application/json
​
jsonrpc
string
default:2.0
​
method
string
default:trace_call
​
params
any[]

Call object, trace types array, and block parameter

​
id
integer
default:1

Response

200 - application/json

Trace result

​
jsonrpc
string
​
id
integer
​
result
object

Trace result object containing output, trace, stateDiff, and vmTrace

Last modified on January 28, 2026