Prepared Transactions

What this covers

How to use the SDK's .prepare() pattern for relayers, smart accounts, gas estimation, and user-operation batching.

When to use this

Use prepared transactions whenever your app should not call walletClient.sendTransaction() directly.

The common pattern

Most write methods in @zkp2p/sdk expose a .prepare() variant that returns:

type PreparedTransaction = {
  to: `0x${string}`;
  data: `0x${string}`;
  value: bigint;
  chainId: number;
};

The main exception is createDeposit(), which uses prepareCreateDeposit().

Prepare a taker transaction

const prepared = await client.signalIntent.prepare({
  depositId: 42n,
  amount: 250_000000n,
  toAddress: '0xBuyerAddress',
  processorName: 'wise',
  payeeDetails: '0xPayeeDetailsHash',
  fiatCurrencyCode: 'USD',
  conversionRate: 1_020000000000000000n,
});

await smartAccount.sendUserOperation({
  calls: [
    {
      to: prepared.to,
      data: prepared.data,
      value: prepared.value,
    },
  ],
});

The same pattern works for:

• signalIntent.prepare()
• fulfillIntent.prepare()
• cancelIntent.prepare()
• releaseFundsToPayer.prepare()
• addFunds.prepare()
• removeFunds.prepare()
• withdrawDeposit.prepare()
• setVaultFee.prepare()
• setVaultMinRate.prepare()
• setVaultConfig.prepare()

Prepare a deposit creation

createDeposit() may also register payee details, so its prepared form returns both the payee payload and the calldata:

const { depositDetails, prepared } = await client.prepareCreateDeposit({
  token: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913',
  amount: 1_000_000000n,
  intentAmountRange: {
    min: 25_000000n,
    max: 250_000000n,
  },
  processorNames: ['wise'],
  payeeData: [{ offchainId: 'maker@example.com' }],
  conversionRates: [[
    { currency: 'USD', conversionRate: '1015000000000000000' },
  ]],
});

console.log(depositDetails);
console.log(prepared.to, prepared.chainId);

Smart-wallet pattern in React

Hooks such as useCreateVault() and useVaultDelegation() let you inject your own sender:

import { useCreateVault } from '@zkp2p/sdk/react';

const { createVault, prepareCreateVault, txHash } = useCreateVault({
  client,
  sendTransaction: async ({ to, data, value }) => {
    return smartWallet.sendTransaction({ to, data, value });
  },
  referrer: ['acme-wallet'],
});

await createVault({
  config: {
    manager: '0xManager',
    feeRecipient: '0xFeeRecipient',
    maxFee: 50_000000000000000n,
    fee: 10_000000000000000n,
    name: 'Acme Vault',
    uri: 'ipfs://vault-metadata',
  },
});

For delegation switches, useVaultDelegation({ sendBatch }) can batch the clear-plus-set sequence into one user operation.

Key points

• Prepared transactions are the right interface for EIP-4337, relayers, simulations, and hardware wallet review screens
• txOverrides.referrer is already encoded into the prepared calldata through ERC-8021 attribution
• prepareCreateDeposit() is the only deposit-creation path that keeps payee registration and calldata preparation together
• If you need the direct wallet path again, call the method itself instead of .prepare()