payment_queryFeeDetails

Description

Returns a detailed fee breakdown, including base fee, length fee, adjusted weight fee, and inclusion tip when applicable.

Parameters

Position	Type	Description
0	string	Signed extrinsic hex
1 (optional)	string	Block hash

Response Fields

Field	Description
inclusionFee	Object containing baseFee, lenFee, adjustedWeightFee
tip	Optional tip included with the extrinsic

Sample Request & Response

{
  "jsonrpc": "2.0",
  "method": "payment_queryFeeDetails",
  "params": ["0x2523053d0002500200…63155"],
  "id": 100
}

{
  "jsonrpc": "2.0",
  "id": 100,
  "result": {
    "inclusionFee": null
  }
}

For subsidized operations (such as staking payouts), the runtime may waive inclusion fees, resulting in null. Regular transfers will return the full fee breakdown.

Code Examples

JavaScript (polkadot.js)

const info = await api.rpc.payment.queryFeeDetails(tx.toHex());
console.log(info.toHuman());

Python (py-substrate-interface)

fee_details = substrate.rpc_request('payment_queryFeeDetails', [extrinsic_hex])['result']
print(fee_details)