payment_queryInfo

Description

Returns fee and weight information for a signed extrinsic without submitting it. Supports planning fee buffers and offline signing workflows.

Parameters

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

Response Fields

Field	Type	Description
weight.ref_time	number	Estimated execution time weight
weight.proof_size	number	Proof size weight
class	string	normal, operational, or mandatory
partialFee	string	Estimated partial fee in plancks

Sample Request & Response

{
  "jsonrpc": "2.0",
  "method": "payment_queryInfo",
  "params": ["0x2523053d0002500200…63155"],
  "id": 99
}

{
  "jsonrpc": "2.0",
  "id": 99,
  "result": {
    "weight": { "ref_time": 3636401000, "proof_size": 18750 },
    "class": "normal",
    "partialFee": "0"
  }
}

note

A zero partialFee indicates the runtime uses fee subsidies (for example, dApp staking payouts). Standard transfers will return positive fees.

Code Examples

JavaScript (polkadot.js)

const tx = api.tx.balances.transferKeepAlive(dest, amount);
const info = await api.rpc.payment.queryInfo(tx.toHex());
console.log(info.toHuman());

Python (py-substrate-interface)

extrinsic_hex = substrate.create_signed_extrinsic(call=call, keypair=keypair).to_hex()
info = substrate.rpc_request('payment_queryInfo', [extrinsic_hex])['result']
print(info)