Reading state

Token info, balances, allowances, fees

The execution module ships viem-backed read helpers for the contract reads every integration ends up doing. Each function takes the rpcUrl directly so they work outside an ExecutionClient instance.

Token info

import { fetchTokenInfo } from "@flashnet/sdk";

const info = await fetchTokenInfo(rpcUrl, tokenAddress);
// { address, symbol, name, decimals }

Reads symbol, name, and decimals in a single multicall. Throws if any of the three fails. Don’t catch the error and fall back to defaults — decimals: 0 masquerading as 18 will silently destroy your amount math.

Balances

import { fetchTokenBalance, fetchNativeBalance } from "@flashnet/sdk";

const erc20Balance = await fetchTokenBalance(rpcUrl, tokenAddress, account);
const nativeBalance = await fetchNativeBalance(rpcUrl, account);

Both return bigint. fetchNativeBalance returns wei; divide by 10n ** 10n to get sats (Flashnet’s native unit is sats scaled to wei via 10^10).

Allowances

import { fetchAllowance } from "@flashnet/sdk";

const allowance = await fetchAllowance(rpcUrl, tokenAddress, owner, spender);

For SparkToken ERC20s, prefer EIP-2612 Permit signatures over standing allowances — the swap path uses Permit and you avoid an extra approval transaction. See Swaps.

Nonce

import { fetchNonce } from "@flashnet/sdk";

const nonce = await fetchNonce(rpcUrl, account);

Returns the next nonce to use for an outgoing transaction. Required when building a signed tx for ExecutionClient.execute.

Fee parameters

import { fetchEip1559Fees } from "@flashnet/sdk/execution";

const fees = await fetchEip1559Fees(rpcUrl);
// { maxFeePerGas: 0n, maxPriorityFeePerGas: 0n } on Flashnet today

fetchEip1559Fees ships from the /execution subpath, not the root. The other read helpers on this page are re-exported at @flashnet/sdk directly.

Flashnet runs zero-gas. The node correctly reports zero, but viem.estimateFeesPerGas() applies its own multipliers and floor that produce non-zero values. fetchEip1559Fees reads the raw node values without that adjustment.

A future fee change (operator policy, partner chain) would surface here. Always fetch instead of hard-coding zero.

Putting it together

The standard pre-flight before an execute intent:

import { fetchNonce } from "@flashnet/sdk";
import { fetchEip1559Fees } from "@flashnet/sdk/execution";

const account = await execClient.getEvmAccount();
const [nonce, fees, { execution }] = await Promise.all([
  fetchNonce(rpcUrl, account.address),
  fetchEip1559Fees(rpcUrl),
  execClient.getNetworkInfo(),
]);

const signedTx = await account.signTransaction({
  chainId: execution.chainId,
  nonce,
  to: targetAddress,
  value: 0n,
  data: calldata,
  gas: 500_000n,
  ...fees,
  type: "eip1559",
});

Multicall

fetchTokenInfo uses Multicall3 internally. The Multicall3 contract is deployed at the canonical cross-chain address (0xcA11bde05977b3631167028862bE2a173976CA11) on every Flashnet chain, so any tooling that already understands Multicall3 works without configuration.

For your own batched reads, point a viem PublicClient at rpcUrl and pass multicallAddress: "0xcA11bde05977b3631167028862bE2a173976CA11".