queryLedgerState_protocolParameters - Cardano

Example code for the queryLedgerState_protocolParameters JSON-RPC method. Complete guide on how to use queryLedgerState_protocolParameters JSON-RPC in GetBlock Web3 documentation.

This method returns the current protocol parameters, including fee coefficients, execution unit prices, and size limits used to validate and price transactions.

Parameters

This method does not require parameters.

Request

cURL

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "queryLedgerState/protocolParameters",
    "id": "getblock.io"
}'

JavaScript

example.js

const response = await fetch(
    'https://go.getblock.io/<ACCESS-TOKEN>/',
    {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({"jsonrpc": "2.0", "method": "queryLedgerState/protocolParameters", "id": "getblock.io"})
    }
);
console.log(await response.json());

Python

example.py

import requests

response = requests.post(
    'https://go.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={"jsonrpc": "2.0", "method": "queryLedgerState/protocolParameters", "id": "getblock.io"}
)

print(response.json())

Response

{
    "jsonrpc": "2.0",
    "method": "queryLedgerState/protocolParameters",
    "result": {
        "minFeeCoefficient": 44,
        "minFeeConstant": {
            "ada": {
                "lovelace": 155381
            }
        },
        "maxBlockBodySize": {
            "bytes": 90112
        },
        "maxTransactionSize": {
            "bytes": 16384
        },
        "stakeCredentialDeposit": {
            "ada": {
                "lovelace": 2000000
            }
        },
        "stakePoolDeposit": {
            "ada": {
                "lovelace": 500000000
            }
        },
        "minUtxoDepositCoefficient": 4310,
        "scriptExecutionPrices": {
            "memory": "577/10000",
            "cpu": "721/10000000"
        }
    },
    "id": "getblock.io"
}

Response Parameters

Field	Type	Description
minFeeCoefficient	integer	Fee charged per byte of transaction size
minFeeConstant	object	Flat fee component in lovelace
maxTransactionSize	object	Maximum transaction size in bytes
stakePoolDeposit	object	Deposit required to register a stake pool
scriptExecutionPrices	object	Prices for script memory and CPU units

Use Cases

• Fee Calculation: Compute the exact fee for a transaction before building it

• Size Validation: Reject transactions that exceed size limits client-side

• Script Budgeting: Price Plutus script execution using unit prices

• Deposit Handling: Read stake and pool deposits when building certificates

Error Handling

Error Code	Message	Description
-32602	Invalid params	A required field is missing or has the wrong type
-32000	Query unavailable	The query is not available in the current ledger era
-32603	Internal error	The node failed to answer the query