Batching Transactions

Smart accounts like Kernel support batching transactions -- rolling multiple transactions into one. This is very useful for simplifying Web3 interactions for your users. For instance, instead of doing approve() followed by transfer(), your user can do both in one transaction.

Batching transactions has a number of important benefits:

• Your user waits for only 1 transaction instead of multiple.
• Your user pays less gas.
• If any transaction in the batch reverts, the entire batch reverts. This ensures that your user won't be stuck in an inconsistent state.
  • This is known as "atomicity."

API

There are two ways to send batched transactions. sendTransaction is a simple API that's good enough for most use cases. If you need fine-grained control over your UserOp, you can use sendUserOperation.

sendTransaction

const txHash = await kernelClient.sendTransaction({
  calls: [
    {
      to: "0xADDRESS",
      value: value,
      data: "0xDATA",
    },
    {
      to: "0xADDRESS",
      value: value,
      data: "0xDATA",
    },
  ],
})

sendUserOperation

You can learn more about the sendUserOperation API here.

To send a UserOp with batching, simply pass an array of calls into encodeCalls.

const userOpHash = await kernelClient.sendUserOperation({
        callData: account.encodeCalls([
          {
            to,
            value,
            data,
          },
          {
            to,
            value,
            data,
          },
        ]),
        // other UserOp params
})