debug_traceBlockByNumber | Monad

Monad API method that returns traces for all transactions in a block specified by block number. Available on Monad via Chainstack.

POST /

debug_traceBlockByNumber

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_traceBlockByNumber",
  "params": [
    "latest",
    {
      "tracer": "callTracer"
    }
  ]
}
'

200

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

Monad API method that returns traces for all transactions in a block specified by block number. This method is useful for analyzing all transaction executions within a single block.

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

• quantity|tag — the block number as a hexadecimal string, or one of the following block tags:
  • latest — the most recent block in the canonical chain
  • earliest — the genesis block
  • pending — the pending state/transactions
• 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 — an array of trace results, one for each transaction in the block. The structure of each trace depends on the tracer used.

debug_traceBlockByNumber code examples

ethers.js

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

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

async function traceBlock() {
  const blockNumber = "latest"; // Or use hex like "0x1234"
  const traces = await provider.send("debug_traceBlockByNumber", [
    blockNumber,
    { tracer: "callTracer" }
  ]);
  console.log(`Traced ${traces.length} transactions`);
  traces.forEach((trace, i) => {
    console.log(`Transaction ${i}:`, trace.result?.type || 'unknown');
  });
}

traceBlock();

Use case

A practical use case for debug_traceBlockByNumber is building block analysis tools that need to understand the complete execution flow of all transactions in a block, such as MEV detection or security monitoring systems.

Body

application/json

id · integer · default: 1

jsonrpc · string · default: 2.0

method · string · default: debug_traceBlockByNumber

params · array

Response

200 - application/json

Array of trace results for each transaction.

jsonrpc · string

id · integer

result · object[]