# Account Abstraction

:::info
These guides cover Ox's low-level primitives. If you are looking for a high-level bundler and
smart account client, check out [Viem's Account Abstraction guides](https://viem.sh/account-abstraction).
:::

## Overview

Account abstraction moves accounts from externally-owned key pairs to smart contracts, changing
how transactions are built, executed, and attributed. Ox ships primitives for each layer of that
stack: [`UserOperation`](/ercs/erc4337/UserOperation) constructs and signs ERC-4337 user
operations, [`Calls`](/ercs/erc7821/Calls) and [`Execute`](/ercs/erc7821/Execute) encode ERC-7821
batched executions, and [`Attribution`](/ercs/erc8021/Attribution) appends ERC-8021 attribution
codes to calldata. To upgrade an existing EOA into a smart account, see
[Delegate with EIP-7702](/guides/transactions/eip-7702).

```ts twoslash
import { Value } from 'ox'
import { UserOperation } from 'ox/erc4337'
import { Execute } from 'ox/erc7821'

// 1. Encode a batch of calls for an ERC-7821 account.
const callData = Execute.encodeData([
  {
    to: '0xcafebabecafebabecafebabecafebabecafebabe',
    value: Value.fromEther('1'),
  },
  {
    data: '0xdeadbeef',
    to: '0xdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef',
  },
])

// 2. Wrap it in an ERC-4337 user operation.
const userOperation = UserOperation.from({
  callData,
  callGasLimit: 300_000n,
  maxFeePerGas: Value.fromGwei('20'),
  maxPriorityFeePerGas: Value.fromGwei('2'),
  nonce: 0n,
  preVerificationGas: 100_000n,
  sender: '0x9f1fdab6458c5fc642fa0f4c5af7473c46837357',
  verificationGasLimit: 100_000n,
})
```

## Guides

<Cards>
  <Card icon="lucide:qr-code" title="Attribute Calldata with ERC-8021" description="Append and parse entity attribution codes on transaction calldata." to="/guides/account-abstraction/erc-8021" />

  <Card icon="lucide:layers" title="Batch Calls with ERC-7821" description="Encode and decode batched executions for the execute interface." to="/guides/account-abstraction/erc-7821" />

  <Card icon="lucide:box" title="Build ERC-4337 User Operations" description="Construct, sign, pack, and submit user operations to bundlers." to="/guides/account-abstraction/user-operations" />

  <Card icon="lucide:sparkles" title="Delegate with EIP-7702" description="Sign authorizations that upgrade an EOA to a smart account." to="/guides/transactions/eip-7702" />
</Cards>