Submit a Transaction¶

Transactions change blockchain state. The examples on this page target only the current Koinos Foundation public testnet, use test tokens with no monetary value, and do not broadcast unless you explicitly opt in.

Configure a signer¶

Keep a dedicated testnet WIF outside source control:

export function signerFromEnvironment(env = process.env) {
  if (!env.TESTNET_WIF) {
    throw new Error("Set TESTNET_WIF to a dedicated, funded testnet key");
  }
  const provider = new Provider(TESTNET.rpc);
  const signer = Signer.fromWif(env.TESTNET_WIF);
  signer.provider = provider;
  return { provider, signer };
}

View complete file · Run example

Encode a transfer¶

This function creates a real testnet KOIN contract operation but does not sign or send it:

export async function createTransferOperation({ from, to, amount }) {
  const contract = new Contract({
    id: TESTNET.koinContract,
    provider: new Provider(TESTNET.rpc),
    abi: transferAbi,
  });
  const { operation } = await contract.functions.transfer(
    {
      from: addressBytes(from),
      to: addressBytes(to),
      value: utils.parseUnits(amount, 8),
    },
    { onlyOperation: true }
  );
  return operation;
}

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Resource and broadcast options¶

export function safeTransactionOptions(env = process.env) {
  return {
    rcLimit: env.RC_LIMIT ?? "100000000",
    broadcast: env.BROADCAST === "true",
  };
}

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BROADCAST is false unless its value is exactly true.

Dry-run preview¶

export async function previewTransfer({ from, to, amount }) {
  const operation = await createTransferOperation({ from, to, amount });
  return { network: TESTNET.name, broadcast: false, operations: [operation] };
}

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npm start executes this safe path and prints the encoded operation.

Receipt handling¶

export function assertSuccessfulReceipt(receipt) {
  if (receipt.reverted) {
    throw new Error(`Transaction reverted: ${(receipt.logs ?? []).join("; ")}`);
  }
  return receipt;
}

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The complete source exports broadcastTransfer. It refuses to run without both BROADCAST=true and TESTNET_WIF. Verify the destination and amount before enabling it.

Best practices¶

Use separate testnet and mainnet wallets.
Never paste a WIF into code, documentation, or an online runner.
Preview and test the operation before broadcasting.
Check receipt.reverted and wait for confirmation where needed.

Continue with multiple operations.