debug_traceBlockByHash

Replays every transaction in a MegaETH block selected by hash and returns execution traces.

Summary

Replays a block selected by hash and returns one execution trace per transaction. The public MegaETH endpoint supports this standard debug method.

Parameters

Position	Name	Type	Required	Description
0	blockHash	DATA, 32 bytes	Yes	Hash of the block to replay.
1	traceConfig	object	Yes on the public gateway	Tracer selection and tracer-specific options. Use {} for the opcode tracer.

Common traceConfig fields include tracer, tracerConfig, and timeout. For example, set tracer to "callTracer" for a nested call frame instead of opcode-level structLogs.

Result

The result is an array ordered by transaction index. Each entry contains txHash and either result or error; the shape of result depends on the selected tracer.

Comparison with Ethereum Standard JSON-RPC

Ethereum Standard

The method replays all transactions in the selected block against its parent state. The genesis block cannot be replayed because it has no parent state.

MegaETH Node Behavior

MegaETH uses the standard geth-compatible tracer options and returns a trace paired with each transaction hash. System transactions may therefore appear in block traces.

MegaETH Public Gateway

The public gateway streams trace responses because they can be large. It requires two positional parameters and supports callTracer.

Errors

The | Scope | column distinguishes method failures from gateway policy errors.

Code	Scope	Message	When it happens
-32602	Method	Invalid params	Either positional parameter is missing or malformed.
-32000	Method	Server error	The block is unknown, its parent state is unavailable, or tracing fails.
-32099	Transport/policy	Payload too large	The request exceeds the public endpoint body limit.

Examples

Endpoint: https://mainnet.megaeth.com/rpc

Capture date: July 24, 2026

Outcome: success

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "debug_traceBlockByHash",
  "params": [
    "0x57804c21b747137075b29ce153b4f559345a3624273660c87e81bd57e7cbbc3d",
    { "tracer": "callTracer" }
  ]
}

The nested call frame is abbreviated below.

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": [
    {
      "txHash": "0xecc262f36652019b75f4cb7315ff19f430fc92efd5a8048948400407d55fd904",
      "result": {
        "from": "0xdeaddeaddeaddeaddeaddeaddeaddeaddead0001",
        "to": "0x4200000000000000000000000000000000000015",
        "gasUsed": "0xb9d56c",
        "type": "CALL"
      }
    }
  ]
}

Sources

• Spec: Ethereum Execution APIs, src/debug/trace.yaml
• Probe: MegaETH Mainnet public endpoint, July 24, 2026