debug_traceCall | Monad

Monad API method that traces a call without creating a transaction on the blockchain. Available on Monad via Chainstack JSON-RPC nodes.

POST /

debug_traceCall

cURL

curl --request POST \
  --url https://monad-testnet.core.chainstack.com/9c5b265f20b3ea5df4f54f70eb74b800/ \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "debug_traceCall",
  "params": [
    {
      "to": "0x760AfE86e5de5fa0Ee542fc7B7B713e1c5425701",
      "data": "0x06fdde03"
    },
    "latest",
    {
      "tracer": "callTracer"
    }
  ]
}
'

200

{
  "jsonrpc": "<string>",
  "id": 123,
  "result": {}
}

Monad API method that traces a call without creating a transaction on the blockchain. This method is similar to eth_call but returns detailed execution traces, making it useful for debugging contract calls before sending actual transactions.

Monad-specific behavior:

• The trace options object parameter must be explicitly provided. Unlike standard EVM clients where this parameter is optional, Monad RPC will return an error (-32602 Invalid params) if the parameter is omitted. Always include the trace options, even if empty ({}).
• When an empty trace options object {} is provided, Monad defaults to callTracer instead of struct logs, because Monad does not currently support opcode-level struct logs at the VM level.

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Parameters

• object — the transaction call object:
  • from (optional) — address the transaction is sent from
  • to — address the transaction is directed to
  • gas (optional) — gas provided for the call
  • gasPrice (optional) — gas price for the call
  • value (optional) — value sent with the call
  • data (optional) — hash of the method signature and encoded parameters
• quantity|tag — the block number as a hexadecimal string, or block tag (latest, earliest, pending).
• object (optional) — the tracer options:
  • tracer — the tracer to use (e.g., callTracer, prestateTracer)
  • tracerConfig — configuration options for the tracer
  • timeout — timeout for the trace operation

Response

• result — the trace result object. The structure depends on the tracer used:
  • For callTracer:
    • type — the call type (CALL, CREATE, etc.)
    • from — sender address
    • to — recipient address
    • value — value transferred
    • gas — gas provided
    • gasUsed — gas used
    • input — call data
    • output — return data
    • calls — nested calls

debug_traceCall code examples

ethers.js

const { ethers } = require("ethers");

const provider = new ethers.JsonRpcProvider("CHAINSTACK_NODE_URL");

async function traceCall() {
  // Trace name() call on Wrapped Monad (WMON) contract
  const tx = {
    to: "0x760AfE86e5de5fa0Ee542fc7B7B713e1c5425701",
    data: "0x06fdde03" // name()
  };

  const trace = await provider.send("debug_traceCall", [
    tx,
    "latest",
    { tracer: "callTracer" }
  ]);
  console.log("Call trace:", JSON.stringify(trace, null, 2));
}

traceCall();

Use case

A practical use case for debug_traceCall is simulating complex contract interactions before sending transactions to understand the execution path, identify potential failures, and verify expected behavior without spending gas.

Body

application/json

id · integer · default: 1

jsonrpc · string · default: 2.0

method · string · default: debug_traceCall

params · array

Response

200 - application/json

The trace result.

jsonrpc · string

id · integer

result · object