Retrieve Internal Transactions from a Transaction Hash

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Internal transactions, also known as “subcalls” or “contract calls,” represent interactions between smart contracts during the execution of a blockchain transaction.

These transactions can be accessed using the debug_traceTransaction method in an Ethereum-compatible RPC interface.

Using "debug_traceTransaction"

The debug_traceTransaction method provides detailed information about all opcodes executed during the transaction. While this is comprehensive, it may be excessive if you only need internal transactions. By passing the parameter { "tracer": "callTracer" } , you can limit the output to only the internal transactions.

Example Request

Below is an example of how to retrieve internal transactions using the debug_traceTransaction method with the callTracer parameter:

curl --location 'https://ethereum-mainnet.gateway.tatum.io' \
--header 'Content-Type: application/json' \
--header 'x-api-key: {YOUR_API_KEY}' \
--data '{
    "jsonrpc":"2.0",
    "method":"debug_traceTransaction",
    "params":["0x16c52c58916c1e91736df3242f3c85a5bb597bcc648c7a2bd05555e8d054168c",
        {
            "tracer":"callTracer",
            "timeout": "90s"
        }
    ],
    "id":1
}'
//Response:
{
    "id": 1,
    "jsonrpc": "2.0",
    "result": {
        "from": "0x7830c87c02e56aff27fa8ab1241711331fa86f43",
        "gas": "0x1e8480",
        "gasUsed": "0x6bd4a",
        "to": "0xa9d1e08c7793af67e9d92fe308d5697fb81d3e43",
        "input": "...",
        "calls": [
            {
                "from": "0xa9d1e08c7793af67e9d92fe308d5697fb81d3e43",
                "gas": "0x15f90",
                "gasUsed": "0x0",
                "to": "0x9fefd35420f40222aaeafafd3721086ce381bdd5",
                "input": "0x",
                "value": "0x1311e50bc2c800",
                "type": "CALL"
            },
            {
                "from": "0xa9d1e08c7793af67e9d92fe308d5697fb81d3e43",
                "gas": "0x15f90",
                "gasUsed": "0x0",
                "to": "0x147b12c06d9e8e3837280f783fd8070848d4412e",
                "input": "0x",
                "value": "0x143ac7788dfdcc000",
                "type": "CALL"
            }
            // Additional internal transactions are listed here...
        ]
    }
}

Key Fields in the Response

from: The address initiating the internal transaction.
to: The recipient address of the internal transaction.
gas: The gas allocated for the internal transaction.
gasUsed: The gas used by the internal transaction.
value: The amount of Ether (or equivalent) transferred.
type: The type of call (e.g., CALL, DELEGATECALL).

Good to Know

Debug and Trace methods may require access to Archival Data
The callTracer is efficient for extracting internal transactions but may still be resource-intensive for large transactions.
A Timeout flag may be required in your request.
Find the list of supported blockchains HERE.
Find more about available authentication methods HERE.

Updated 2 days ago