Fetch Data via the Kotlin SDK

Kaptos exposes data-reading APIs across fullnode REST endpoints, indexer-backed endpoints, and Move view functions.

Result-based handling

Network calls return Result<Ok, Err>, so you can choose explicit branching or fail-fast unwrapping.

val ledgerInfoResult = aptos.getLedgerInfo()

when (ledgerInfoResult) {
  is Result.Ok -> println("Ledger version: ${ledgerInfoResult.value.ledgerVersion}")
  is Result.Err -> println("Failed to read ledger info: ${ledgerInfoResult.error.message}")
}

If you want fail-fast semantics:

val ledgerInfo = aptos.getLedgerInfo().expect("Failed to fetch ledger info")

For more patterns, see Handle SDK Data Fetch Responses.

Read general chain data

val chainId = aptos.getChainId().expect("Failed to fetch chain id")
val latestBlock = aptos.getBlockByHeight(ledgerHeight = 1, withTransactions = true).expect("Failed to fetch block info")

Read account data

val address = AccountAddress.fromString("0x1")

val accountInfo = aptos.getAccountInfo(accountAddress = address).expect("Failed to fetch account info")
val modules = aptos.getAccountModules(accountAddress = address) { limit = 20 }.expect("Failed to fetch modules")
val resources = aptos.getAccountResources(accountAddress = address) { limit = 50 }.expect("Failed to fetch resources")

Read balances

Indexer-backed APT balance:

val aptBalance = aptos.getAccountAPTAmount(accountAddress = address).expect("Failed to fetch APT balance")

Smart-contract view path for a specific coin type:

val aptBalanceFromView =
  aptos
    .getAccountCoinAmountFromSmartContract(
      accountAddress = address,
      coinType = MoveValue.MoveStructId("0x1::aptos_coin::AptosCoin"),
    )
    .expect("Failed to fetch coin balance from smart contract")

Read via Move view functions

Use view<T>() for custom read-only Move calls.

val payload =
  InputViewFunctionData(
    function = "0x1::chain_id::get",
    typeArguments = emptyList(),
    functionArguments = emptyList(),
  )

val viewResult =
  aptos
    .view<List<MoveValue.MoveUint8Type>>(payload)
    .expect("Failed to execute view")

val chainIdFromView = viewResult.first().value