trace_replayBlockTransactions

The trace_replayBlockTransactions method replays all transactions in a specified block and returns detailed trace information for each transaction. This provides insights into the execution flow of transactions, allowing for detailed analysis and debugging.

Use Cases

• Analyzing transaction execution flows in specific blocks
• Debugging complex smart contract interactions
• Understanding state changes from transaction execution
• Auditing and verifying transaction results
• Gas optimization research
• Investigating failed transactions
• Research and analysis of historical blocks
• Testing contract behavior under specific block conditions
• Identifying patterns across multiple transactions in a block
• Verifying consensus rules at the transaction level

Method Details

This method replays all transactions in a block with detailed trace information.

Response Example

{
	"jsonrpc": "2.0",
	"id": 1,
	"result": [
		{
			"output": "0x0000000000000000000000000000000000000000000000000000000000000001",
			"stateDiff": {
				"0x1234567890123456789012345678901234567890": {
					"balance": {
						"*": {
							"from": "0x100",
							"to": "0x110"
						}
					},
					"code": "=",
					"nonce": {
						"*": {
							"from": "0x10",
							"to": "0x11"
						}
					},
					"storage": {
						"0x0000000000000000000000000000000000000000000000000000000000000001": {
							"*": {
								"from": "0x0000000000000000000000000000000000000000000000000000000000000000",
								"to": "0x0000000000000000000000000000000000000000000000000000000000000001"
							}
						}
					}
				}
			},
			"trace": [
				{
					"action": {
						"callType": "call",
						"from": "0x71c7656ec7ab88b098defb751b7401b5f6d8976f",
						"gas": "0x4c40d",
						"input": "0xa9059cbb000000000000000000000000ea674fdde714fd979de3edf0f56aa9716b898ec80000000000000000000000000000000000000000000000002b5e3af16b1880000",
						"to": "0xdac17f958d2ee523a2206206994597c13d831ec7",
						"value": "0x0"
					},
					"result": {
						"gasUsed": "0x9868",
						"output": "0x0000000000000000000000000000000000000000000000000000000000000001"
					},
					"subtraces": 0,
					"traceAddress": [],
					"type": "call"
				}
			],
			"transactionHash": "0x69f8de1af3129dc3b1adb5b3c1577476f737f9335f156e177b48c2ed88f3f7c4",
			"vmTrace": {
				"code": "0x60606040...",
				"ops": [
					{
						"cost": 3,
						"ex": {
							"mem": null,
							"push": ["0x60"],
							"store": null,
							"used": 16723979
						},
						"pc": 0,
						"sub": null
					}
					// Additional ops...
				]
			}
		}
		// Additional transaction traces...
	]
}

Trace Types

The traceTypes parameter accepts an array of the following values:

• trace: The basic trace of transaction execution
• vmTrace: A detailed trace of the EVM execution
• stateDiff: State changes resulting from the transaction

You can request any combination of these trace types.

State Diff Format

The state diff format uses the following symbols:

• "=": No change in the value
• "+": The value was created
• "-": The value was deleted
• "*": The value was modified, with "from" and "to" values

VM Trace Format

The VM trace contains:

• code: The EVM bytecode being executed
• ops: Array of operations with:
• cost: Gas cost of the operation
• ex: Execution result (memory, stack, storage)
• pc: Program counter
• sub: Information for subcalls

Trace Format

The trace format shows the execution path:

• action: Details about the call
• result: Result of the call
• subtraces: Number of child calls
• traceAddress: Position in the call tree
• type: Type of operation (call, create, suicide)

Important Notes

• This method is computationally intensive and may take time to complete
• Requires trace APIs to be enabled on the Ethereum node
• Not all Ethereum clients support this method
• The response size can be very large for blocks with many transactions
• Consider limiting the trace types for better performance
• Empty blocks will return an empty array
• Historical blocks can only be traced if the node maintains archive data
• For blocks with complex transactions, the response might be extremely large
• Each trace type adds significantly to the response size
• Different clients may implement slight variations of the trace formats

Block Tags

The blockNumber parameter accepts:

• Hex-encoded block number (0x1b4)
• latest: The most recent mined block
• earliest: The genesis block
• pending: Currently pending block (transactions waiting to be mined)

See also

• trace_block - Get basic traces for all transactions in a block
• trace_call - Execute and trace a call without creating a transaction
• debug_traceTransaction - Get detailed execution trace for a single transaction