Smart Accounts Kit

npm install @metamask/smart-accounts-kit@0.3.0

forge install metamask/delegation-framework@v1.3.0

import { Implementation, toMetaMaskSmartAccount } from '@metamask/smart-accounts-kit'
import { privateKeyToAccount } from 'viem/accounts'

const account = privateKeyToAccount('0x...')

const smartAccount = await toMetaMaskSmartAccount({
  client: publicClient,
  implementation: Implementation.Hybrid,
  deployParams: [account.address, [], [], []],
  deploySalt: '0x',
  signer: { account },
})

import { createDelegation } from '@metamask/smart-accounts-kit'
import { parseUnits } from 'viem'

const delegation = createDelegation({
  to: delegateAddress,
  from: delegatorSmartAccount.address,
  environment: delegatorSmartAccount.environment,
  scope: {
    type: 'erc20TransferAmount',
    tokenAddress: '0x1c7D4B196Cb0C7B01d743Fbc6116a902379C7238',
    maxAmount: parseUnits('10', 6),
  },
  caveats: [
    { type: 'timestamp', afterThreshold: now, beforeThreshold: expiry },
    { type: 'limitedCalls', limit: 5 },
  ],
})

const signature = await smartAccount.signDelegation({ delegation })
const signedDelegation = { ...delegation, signature }

import { createExecution, ExecutionMode } from '@metamask/smart-accounts-kit'
import { DelegationManager } from '@metamask/smart-accounts-kit/contracts'
import { encodeFunctionData, erc20Abi } from 'viem'

const callData = encodeFunctionData({
  abi: erc20Abi,
  args: [recipient, parseUnits('1', 6)],
  functionName: 'transfer',
})

const execution = createExecution({ target: tokenAddress, callData })

const redeemCalldata = DelegationManager.encode.redeemDelegations({
  delegations: [[signedDelegation]],
  modes: [ExecutionMode.SingleDefault],
  executions: [[execution]],
})

// Via smart account
const userOpHash = await bundlerClient.sendUserOperation({
  account: delegateSmartAccount,
  calls: [{ to: delegateSmartAccount.address, data: redeemCalldata }],
})

// Via EOA
const txHash = await delegateWalletClient.sendTransaction({
  to: environment.DelegationManager,
  data: redeemCalldata,
})

import { erc7715ProviderActions } from '@metamask/smart-accounts-kit/actions'

const walletClient = createWalletClient({
  transport: custom(window.ethereum),
}).extend(erc7715ProviderActions())

const grantedPermissions = await walletClient.requestExecutionPermissions([
  {
    chainId: chain.id,
    expiry: now + 604800,
    signer: {
      type: 'account',
      data: { address: sessionAccount.address },
    },
    permission: {
      type: 'erc20-token-periodic',
      data: {
        tokenAddress,
        periodAmount: parseUnits('10', 6),
        periodDuration: 86400,
        justification: 'Transfer 10 USDC daily',
      },
    },
    isAdjustmentAllowed: true,
  },
])

// Smart account
import { erc7710BundlerActions } from '@metamask/smart-accounts-kit/actions'

const bundlerClient = createBundlerClient({
  client: publicClient,
  transport: http(bundlerUrl),
}).extend(erc7710BundlerActions())

const permissionsContext = grantedPermissions[0].context
const delegationManager = grantedPermissions[0].signerMeta.delegationManager

const userOpHash = await bundlerClient.sendUserOperationWithDelegation({
  publicClient,
  account: sessionAccount,
  calls: [
    {
      to: tokenAddress,
      data: calldata,
      permissionsContext,
      delegationManager,
    },
  ],
})

// EOA
import { erc7710WalletActions } from '@metamask/smart-accounts-kit/actions'

const walletClient = createWalletClient({
  account: sessionAccount,
  chain,
  transport: http(),
}).extend(erc7710WalletActions())

const txHash = await walletClient.sendTransactionWithDelegation({
  to: tokenAddress,
  data: calldata,
  permissionsContext,
  delegationManager,
})

npm install permissionless

import { getAccountNonce } from 'permissionless'
import { entryPoint07Address } from 'viem/account-abstraction'

// Get nonce for a specific key
const parallelNonce = await getAccountNonce(publicClient, {
  address: smartAccount.address,
  entryPointAddress: entryPoint07Address,
  key: BigInt(Date.now()), // Unique key for parallel execution
})

const userOpHash = await bundlerClient.sendUserOperation({
  account: smartAccount,
  calls: [redeemCalldata],
  nonce: parallelNonce, // Properly encoded 256-bit nonce
})

import { getAccountNonce } from 'permissionless'
import { entryPoint07Address } from 'viem/account-abstraction'

// Execute multiple redemption UserOps in parallel
const redeems = await Promise.all(
  delegations.map(async (delegation, index) => {
    // Generate unique key for this operation
    const nonceKey = BigInt(Date.now()) + BigInt(index * 1000)
    
    // Get properly encoded nonce for this key
    const nonce = await getAccountNonce(publicClient, {
      address: backendSmartAccount.address,
      entryPointAddress: entryPoint07Address,
      key: nonceKey,
    })
    
    const redeemCalldata = DelegationManager.encode.redeemDelegations({
      delegations: [[delegation]],
      modes: [ExecutionMode.SingleDefault],
      executions: [[execution]],
    })
    
    return bundlerClient.sendUserOperation({
      account: backendSmartAccount,
      calls: [{ to: backendSmartAccount.address, data: redeemCalldata }],
      nonce, // Parallel execution enabled via unique key
    })
  })
)

// EntryPoint: nonceSequenceNumber[sender][key] | (uint256(key) << 64)
const key = BigInt(Date.now())
const sequence = 0n // New key starts at sequence 0
const nonce = sequence | (key << 64n)
// Or equivalently: (key << 64n) | sequence

const results = await Promise.allSettled(redeems)

results.forEach((result, index) => {
  if (result.status === 'rejected') {
    // Check for specific errors
    if (result.reason.message?.includes('AA25')) {
      console.error(`Nonce collision for op ${index}`)
    }
    // Handle or retry
  }
})

// 1. Backend creates its own smart account as delegate
const backendAccount = await toMetaMaskSmartAccount({
  client: publicClient,
  implementation: Implementation.Hybrid,
  deployParams: [backendOwner.address, [], [], []],
  deploySalt: '0x',
  signer: { account: backendOwner },
})

// 2. Backend redeems by sending UserOp FROM its account
const userOpHash = await bundlerClient.sendUserOperation({
  account: backendAccount,
  calls: [{
    to: backendAccount.address,
    data: DelegationManager.encode.redeemDelegations({
      delegations: [[userDelegation]],
      modes: [ExecutionMode.SingleDefault],
      executions: [[swapExecution]],
    })
  }],
})