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

# trace_call | Arc

> Arc API method that traces a call without creating a transaction. This provides detailed execution traces using the Parity/OpenEthereum trace format.

Arc API method that traces a call without creating a transaction. This provides detailed execution traces using the Parity/OpenEthereum trace format.

## 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:

<CodeGroup>
  ```javascript ethers.js theme={"system"}
  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();
  ```

  ```python web3.py theme={"system"}
  from web3 import Web3

  node_url = "CHAINSTACK_NODE_URL"
  web3 = Web3(Web3.HTTPProvider(node_url))

  # pathUSD token address
  PATHUSD = "0x20c0000000000000000000000000000000000000"
  TARGET_ADDRESS = "0x9729187D9E8Bbefa8295F39f5634cA454dd9d294"

  # balanceOf(address) calldata
  data = "0x70a08231000000000000000000000000" + TARGET_ADDRESS[2:].lower()

  result = web3.provider.make_request("trace_call", [
      {
          "to": PATHUSD,
          "data": data
      },
      ["trace", "stateDiff"],
      "latest"
  ])

  trace_result = result['result']
  print(f"Output: {trace_result['output']}")
  print(f"Traces: {len(trace_result['trace'])}")

  if trace_result.get('stateDiff'):
      print(f"State changes: {len(trace_result['stateDiff'])} addresses affected")
  ```

  ```bash cURL theme={"system"}
  curl -X POST "CHAINSTACK_NODE_URL" \
    -H "Content-Type: application/json" \
    -d '{
      "jsonrpc": "2.0",
      "method": "trace_call",
      "params": [
        {
          "to": "0x20c0000000000000000000000000000000000000",
          "data": "0x70a082310000000000000000000000009729187d9e8bbefa8295f39f5634ca454dd9d294"
        },
        ["trace", "stateDiff"],
        "latest"
      ],
      "id": 1
    }'
  ```
</CodeGroup>


## OpenAPI

````yaml openapi/arc_node_api/debug_and_trace/trace_call.json POST /
openapi: 3.0.0
info:
  title: Chainstack Node API
  version: 1.0.0
  description: This is an API for interacting with a Chainstack node.
servers:
  - url: https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c
security: []
paths:
  /:
    post:
      tags:
        - upload
      summary: trace_call
      operationId: trace_call
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                id:
                  type: integer
                  default: 1
                jsonrpc:
                  type: string
                  default: '2.0'
                method:
                  type: string
                  default: trace_call
                params:
                  type: array
                  default:
                    - from: '0x5d20879655df3c1e04ab111af0009ad650e762f0'
                      to: '0x7798f2eb73c1dd8fa8086d780d5cf114a10f528e'
                      gas: '0xf4240'
                      data: 0x
                    - - trace
                    - latest
      responses:
        '200':
          description: Returns the result of trace_call.
          content:
            application/json:
              schema:
                type: object
                properties:
                  jsonrpc:
                    type: string
                  id:
                    type: integer
                  result:
                    type: object
                    properties:
                      output:
                        type: string
                      stateDiff:
                        type: object
                        nullable: true
                      trace:
                        type: array
                        items:
                          type: object
                          properties:
                            type:
                              type: string
                            action:
                              type: object
                              properties:
                                from:
                                  type: string
                                callType:
                                  type: string
                                gas:
                                  type: string
                                input:
                                  type: string
                                to:
                                  type: string
                                value:
                                  type: string
                            error:
                              type: string
                            result:
                              type: object
                              properties:
                                gasUsed:
                                  type: string
                                output:
                                  type: string
                            subtraces:
                              type: integer
                            traceAddress:
                              type: array
                              items:
                                type: object
                      vmTrace:
                        type: object
                        nullable: true
              example:
                jsonrpc: '2.0'
                id: 1
                result:
                  output: 0x
                  stateDiff: null
                  trace:
                    - type: call
                      action:
                        from: '0x5d20879655df3c1e04ab111af0009ad650e762f0'
                        callType: call
                        gas: '0xef038'
                        input: 0x
                        to: '0x7798f2eb73c1dd8fa8086d780d5cf114a10f528e'
                        value: '0x0'
                      error: Reverted
                      result:
                        gasUsed: '0x2e'
                        output: 0x
                      subtraces: 0
                      traceAddress: []
                  vmTrace: null

````