state_getStorage

Description

Retrieves a storage value from the Moonbase Alpha state at a given key. Storage keys are constructed from pallet name, storage item name, and optional parameters. The returned value is SCALE-encoded and needs to be decoded according to the storage item's type.

Parameters

Parameter	Type	Required	Description
storageKey	string	Yes	Hex-encoded storage key
blockHash	string	No	Block hash to query state at. If omitted, uses latest block

Quick Examples

cURL

# Read runtime :code (Wasm) at latest
curl -X POST https://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","id":1,"method":"state_getStorage","params":["0x3a636f6465"]}'

# Read the same key at a specific block
curl -X POST https://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","id":1,"method":"state_getStorage","params":["0x3a636f6465","0x9d44ea4103132b9ab5addc69bfe96065e0b0d58c44591b9f72bf448ca3877549"]}'

JavaScript (polkadot.js)

import { ApiPromise, WsProvider } from '@polkadot/api';

async function main() {
  const api = await ApiPromise.create({ provider: new WsProvider('${S.wsBase}') });

  // High-level query: System.Account for a known AccountId (Moonbase uses 20-byte AccountId)
  const account = await api.query.system.account('${S.accountId}');
  console.log('Account nonce:', account.nonce.toString());
  console.log('Free balance:', account.data.free.toString());

  // Raw storage query: runtime :code key
  const raw = await api.rpc.state.getStorage('${S.storageCodeKey}');
  console.log('Runtime code length:', raw?.toU8a().length ?? 0);

  // Historical query
  const at = await api.rpc.chain.getBlockHash(${S.blockNumber});
  const historical = await api.rpc.state.getStorage('${S.storageCodeKey}', at);
  console.log('Historical code length:', historical?.toU8a().length ?? 0);

  await api.disconnect();
}

main().catch(console.error);

Python (py-substrate-interface)

from substrateinterface import SubstrateInterface

api = SubstrateInterface(
    url='${S.wsBase}',
    ss58_format=1287,
    type_registry_preset='substrate-node-template'
)

# High-level System.Account
info = api.query('System', 'Account', params=['${S.accountId}'])
print('Nonce:', info.value['nonce'])
print('Free:', info.value['data']['free'])

# Raw :code key
raw = api.rpc_request('state_getStorage', ['${S.storageCodeKey}'])['result']
print('Code (hex, truncated):', raw[:66] + '…')

Storage Key Construction

Storage keys follow the pattern:

twox128(pallet_name) + twox128(storage_item_name) + hasher(key_params)

Common Storage Keys

Storage	Key Prefix	Description
System.Account	twox128("System") + twox128("Account")	Account information
:code	0x3a636f6465	Runtime Wasm blob

For Account maps, the key suffix uses blake2_128_concat(accountId) where accountId is 20 bytes on Moonbase Alpha.

Notes

• Responses are SCALE-encoded; prefer high-level SDKs to decode types correctly.
• Use state_getKeysPaged to enumerate keys for large prefixes efficiently.
• Historical queries require a block hash; prefer finalized hashes for consistency.