debug_traceCall

Traces the execution of eth_call and provides detailed information about each step of the execution. This is similar to trace_call.

Parameters

1. Object - The transaction call object with the following:

   • from(optional): the address the transaction is sent from.

   • to(required): the address the transaction is sent to.

   • gas(optional): Integer of the gas provided for the transaction execution. eth_call consumes zero gas, but this parameter may be needed by some executions.

   • gasPrice(optional): Integer of the gasPrice used for each paid gas.

   • value(optional): Integer of the value sent with this transaction.

   • data(optional): Hash of the method signature and encoded parameters. For details see Ethereum Contract ABI in the Solidity documentation.

2. Quantity or tag - choose 1 of the following options:

   • A hexadecimal block number.

   • "earliest" - the earliest/genesis block.

   • "latest" - the latest mined block.

   • "safe" - the latest safe head block.

   • "finalized" - the latest finalized block.

   • "pending" - the pending state/transactions.

3. Tracer - choose from one of these options:

   • 4byteTracer - Solidity contract functions are addressed using the first four byte of the Keccak-256 hash of their signature. This tracer monitors and analyzes the usage of specific function signatures within smart contracts by capturing their unique first four bytes.

   • callTracer - collects data about all call frames executed within a transaction, creating a hierarchical list of call frames structured mirroring the EVM's operations. This is useful for debugging and analytical purposes.

   • prestateTracer - captures and analyzes the state of the blockchain before the execution of a specific transaction. It helps in understanding the state changes and effects that a transaction will have on the blockchain's data and accounts before the transaction is actually executed.

   • noopTracer - returns empty results. This is used for testing purpose.

   • opcountTracer - count and track the number of operations (or opcodes) executed during a specific transaction.

   • unigramTracer - counts the frequency of occurrence of each opcode.

   • bigramTracer - a bigram refers to a sequence of two bytes or characters. This tracer is designed to observe and provide insights into the patterns and occurrences of these two-byte sequences as they appear within the data of executed transactions.

   • trigramTracer - a trigram refers to a sequence of three bytes or characters. This tracer is designed to observe and provide insights into the patterns and occurrences of these three-byte sequences as they appear within the data of executed transactions.

   • evmdisTracer - generates the bytecode disassembly of executed transactions, providing developers with insights into how smart contracts operate at a low-level bytecode level for debugging, security audits, and performance optimization purposes.

Sample Request

curl https://lb.nodies.app/v1/<INSERT URL> \
   -H "x-api-key: <API-KEY>" \
   -X POST \
   -H "Content-Type: application/json" \
   -d '{ 
  "id": 1,
  "jsonrpc": "2.0",
  "method": "debug_traceCall",
  "params": [
    {
      "from": "0x035C9c507149Fa30b17F9735BF97B4642C73464f",
      "to": "0x0000000000a39bb272e79075ade125fd351887ac",
      "gas": "0x1E9EF",
      "gasPrice": "0xBD32B2ABC",
      "data": "0xd0e30db0"
    },
    "latest",
    {
      "tracer": "callTracer"
    }
  ]
}'

Sample Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "from": "0x035c9c507149fa30b17f9735bf97b4642c73464f",
    "gas": "0x197a7",
    "gasUsed": "0x7657",
    "to": "0x0000000000a39bb272e79075ade125fd351887ac",
    "input": "0xd0e30db0",
    "calls": [
      {
        "from": "0x0000000000a39bb272e79075ade125fd351887ac",
        "gas": "0x17eab",
        "gasUsed": "0x10ff",
        "to": "0x01a656024de4b89e2d0198bf4d468e8fd2358b17",
        "input": "0xd0e30db0",
        "type": "DELEGATECALL"
      }
    ],
    "value": "0x0",
    "type": "CALL"
  }
}