Post-Hook Examples

Post-hooks let you chain actions after a swap settles — stake received tokens, bridge them to another chain, or deposit into a vault. This tutorial shows complete worked examples for each pattern.

Post-hooks that need to act on received tokens must use CoW Shed. Without it, the tokens land in your wallet but the post-hook executes in the HooksTrampoline contract, which can’t access your wallet.

How Post-Hooks Work

Order settles → tokens sent to receiver
Post-hook executes in HooksTrampoline context

With CoW Shed:
Order settles → tokens sent to CoW Shed proxy (your deterministic smart account)
Post-hook calls CoW Shed proxy → proxy executes pre-signed operations on your tokens

Example 1: Swap → Stake (Lido stETH)

Swap USDC for WETH, then stake the WETH into Lido to receive stETH.

import {
  SupportedChainId,
  OrderKind,
  TradingSdk,
  TradeParameters,
  SwapAdvancedSettings,
} from '@cowprotocol/sdk-trading'
import { CowShedSdk } from '@cowprotocol/sdk-cow-shed'
import { ViemAdapter } from '@cowprotocol/sdk-viem-adapter'
import { encodeFunctionData, parseEther, createPublicClient, http, privateKeyToAccount } from 'viem'
import { mainnet } from 'viem/chains'

const WETH = '0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2'
const USDC = '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48'
const LIDO_WSTETH = '0x7f39C581F595B53c5cb19bD0b3f8dA6c935E2Ca0'

const signer = privateKeyToAccount('YOUR_PRIVATE_KEY' as `0x${string}`)

const adapter = new ViemAdapter({
  provider: createPublicClient({ chain: mainnet, transport: http('YOUR_RPC_URL') }),
  signer,
})

const tradingSdk = new TradingSdk({
  chainId: SupportedChainId.MAINNET,
  appCode: 'swap-and-stake',
}, {}, adapter)

const cowShedSdk = new CowShedSdk()

// 1. Prepare the staking call via CoW Shed
const stakeAmount = parseEther('1') // Amount of WETH to stake

const hookResult = await cowShedSdk.signCalls({
  calls: [
    // Approve Lido to spend WETH
    {
      target: WETH,
      callData: encodeFunctionData({
        abi: [{
          name: 'approve',
          type: 'function',
          inputs: [
            { name: 'spender', type: 'address' },
            { name: 'amount', type: 'uint256' },
          ],
          outputs: [{ type: 'bool' }],
        }],
        functionName: 'approve',
        args: [LIDO_WSTETH, stakeAmount],
      }),
      value: 0n,
      allowFailure: false,
      isDelegateCall: false,
    },
    // Wrap WETH → wstETH via Lido
    {
      target: LIDO_WSTETH,
      callData: encodeFunctionData({
        abi: [{
          name: 'wrap',
          type: 'function',
          inputs: [{ name: '_wstETHAmount', type: 'uint256' }],
          outputs: [{ type: 'uint256' }],
        }],
        functionName: 'wrap',
        args: [stakeAmount],
      }),
      value: 0n,
      allowFailure: false,
      isDelegateCall: false,
    },
  ],
  signer,
  chainId: SupportedChainId.MAINNET,
  deadline: BigInt(Math.floor(Date.now() / 1000) + 3600),
})

// 2. Create the swap order with post-hook
const parameters: TradeParameters = {
  kind: OrderKind.SELL,
  sellToken: USDC,
  sellTokenDecimals: 6,
  buyToken: WETH,
  buyTokenDecimals: 18,
  amount: '3000000000', // 3,000 USDC
  receiver: hookResult.cowShedAccount, // Tokens go to CoW Shed
}

const advancedSettings: SwapAdvancedSettings = {
  appData: {
    metadata: {
      hooks: {
        post: [{
          target: hookResult.signedMulticall.to,
          callData: hookResult.signedMulticall.data,
          gasLimit: hookResult.gasLimit,
        }],
      },
    },
  },
}

const { orderId } = await tradingSdk.postSwapOrder(parameters, advancedSettings)
console.log('Swap → Stake order created:', orderId)

Example 2: Swap → Bridge (Across Protocol)

Swap tokens on Ethereum, then bridge the received tokens to Arbitrum via Across.

const ACROSS_SPOKE_POOL = '0x5c7BCd6E7De5423a257D81B442095A1a6ced35C5'

// 1. Prepare the bridge call via CoW Shed
const bridgeAmount = 1000n * 10n ** 6n // 1,000 USDC to bridge

const bridgeHookResult = await cowShedSdk.signCalls({
  calls: [
    // Approve Across SpokePool
    {
      target: USDC,
      callData: encodeFunctionData({
        abi: [{
          name: 'approve',
          type: 'function',
          inputs: [
            { name: 'spender', type: 'address' },
            { name: 'amount', type: 'uint256' },
          ],
          outputs: [{ type: 'bool' }],
        }],
        functionName: 'approve',
        args: [ACROSS_SPOKE_POOL, bridgeAmount],
      }),
      value: 0n,
      allowFailure: false,
      isDelegateCall: false,
    },
    // Initiate bridge deposit
    {
      target: ACROSS_SPOKE_POOL,
      callData: encodeFunctionData({
        abi: [{
          name: 'depositV3',
          type: 'function',
          inputs: [
            { name: 'depositor', type: 'address' },
            { name: 'recipient', type: 'address' },
            { name: 'inputToken', type: 'address' },
            { name: 'outputToken', type: 'address' },
            { name: 'inputAmount', type: 'uint256' },
            { name: 'outputAmount', type: 'uint256' },
            { name: 'destinationChainId', type: 'uint256' },
            { name: 'exclusiveRelayer', type: 'address' },
            { name: 'quoteTimestamp', type: 'uint32' },
            { name: 'fillDeadline', type: 'uint32' },
            { name: 'exclusivityDeadline', type: 'uint32' },
            { name: 'message', type: 'bytes' },
          ],
          outputs: [],
        }],
        functionName: 'depositV3',
        args: [
          signer.address,              // depositor (CoW Shed account)
          signer.address,              // recipient on destination
          USDC,                         // input token
          USDC,                         // output token (same on Arbitrum)
          bridgeAmount,                 // input amount
          bridgeAmount * 995n / 1000n,  // output amount (0.5% bridge fee)
          42161n,                       // Arbitrum chain ID
          '0x0000000000000000000000000000000000000000',
          Math.floor(Date.now() / 1000),
          Math.floor(Date.now() / 1000) + 7200,
          0,
          '0x',
        ],
      }),
      value: 0n,
      allowFailure: false,
      isDelegateCall: false,
    },
  ],
  signer,
  chainId: SupportedChainId.MAINNET,
  deadline: BigInt(Math.floor(Date.now() / 1000) + 3600),
})

// 2. Create the swap + bridge order
const { orderId } = await tradingSdk.postSwapOrder(
  {
    kind: OrderKind.SELL,
    sellToken: WETH,
    sellTokenDecimals: 18,
    buyToken: USDC,
    buyTokenDecimals: 6,
    amount: parseEther('1').toString(), // Sell 1 WETH
    receiver: bridgeHookResult.cowShedAccount,
  },
  {
    appData: {
      metadata: {
        hooks: {
          post: [{
            target: bridgeHookResult.signedMulticall.to,
            callData: bridgeHookResult.signedMulticall.data,
            gasLimit: bridgeHookResult.gasLimit,
          }],
        },
      },
    },
  },
)

console.log('Swap → Bridge order created:', orderId)

CoW Swap also supports native cross-chain swaps through the UI, which handles bridging automatically without custom hooks.

Example 3: Swap → Vault Deposit (ERC-4626)

Swap tokens and deposit into an ERC-4626 yield vault:

const YIELD_VAULT = '0xYourERC4626VaultAddress'
const DAI = '0x6B175474E89094C44Da98b954EedeAC495271d0F'

const depositAmount = parseEther('5000') // 5,000 DAI

const vaultHookResult = await cowShedSdk.signCalls({
  calls: [
    // Approve vault
    {
      target: DAI,
      callData: encodeFunctionData({
        abi: [{
          name: 'approve',
          type: 'function',
          inputs: [
            { name: 'spender', type: 'address' },
            { name: 'amount', type: 'uint256' },
          ],
          outputs: [{ type: 'bool' }],
        }],
        functionName: 'approve',
        args: [YIELD_VAULT, depositAmount],
      }),
      value: 0n,
      allowFailure: false,
      isDelegateCall: false,
    },
    // Deposit into ERC-4626 vault
    {
      target: YIELD_VAULT,
      callData: encodeFunctionData({
        abi: [{
          name: 'deposit',
          type: 'function',
          inputs: [
            { name: 'assets', type: 'uint256' },
            { name: 'receiver', type: 'address' },
          ],
          outputs: [{ type: 'uint256' }],
        }],
        functionName: 'deposit',
        args: [depositAmount, signer.address],
      }),
      value: 0n,
      allowFailure: false,
      isDelegateCall: false,
    },
  ],
  signer,
  chainId: SupportedChainId.MAINNET,
  deadline: BigInt(Math.floor(Date.now() / 1000) + 3600),
})

const { orderId } = await tradingSdk.postSwapOrder(
  {
    kind: OrderKind.SELL,
    sellToken: USDC,
    sellTokenDecimals: 6,
    buyToken: DAI,
    buyTokenDecimals: 18,
    amount: '5000000000', // 5,000 USDC
    receiver: vaultHookResult.cowShedAccount,
  },
  {
    appData: {
      metadata: {
        hooks: {
          post: [{
            target: vaultHookResult.signedMulticall.to,
            callData: vaultHookResult.signedMulticall.data,
            gasLimit: vaultHookResult.gasLimit,
          }],
        },
      },
    },
  },
)

console.log('Swap → Vault deposit order created:', orderId)

Key Considerations

Gas Limits

Post-hook operation	Recommended gas limit
ERC-20 approve	50,000
Lido wrap/unwrap	100,000
Bridge deposit (Across)	200,000
ERC-4626 deposit	150,000
CoW Shed multicall overhead	+50,000

Amount Handling

Post-hooks execute with a fixed amount — the exact callData you sign. If the swap returns more tokens than expected (surplus), the extra tokens remain in the CoW Shed proxy. To handle variable amounts, you can:

Use the full balance in the CoW Shed proxy (if the protocol supports type(uint256).max)
Set the post-hook amount to the order’s buyAmount (guaranteed minimum)

Failure Modes

If a post-hook fails, the entire settlement transaction reverts — your swap doesn’t execute either. Ensure:

Sufficient gas limits for each hook operation
Correct token approvals in the hook chain
The target protocol accepts the deposit/stake/bridge at the time of execution

Next Steps

Hooks: Getting Started — create your first hook step-by-step
Hook Store — browse pre-built hooks or publish your own
Hooks Guide — complete hooks reference
Account Abstraction (CoW Shed) — CoW Shed setup and API
Hook dApp Development — build hooks for the CoW Swap UI

Overview

Trading Tutorials

Advanced

Hooks

Widget

Reference

How Post-Hooks Work

Example 1: Swap → Stake (Lido stETH)

Example 2: Swap → Bridge (Across Protocol)

Example 3: Swap → Vault Deposit (ERC-4626)

Key Considerations

Gas Limits

Amount Handling

Failure Modes

Next Steps

​How Post-Hooks Work

​Example 1: Swap → Stake (Lido stETH)

​Example 2: Swap → Bridge (Across Protocol)

​Example 3: Swap → Vault Deposit (ERC-4626)

​Key Considerations

​Gas Limits

​Amount Handling

​Failure Modes

​Next Steps

How Post-Hooks Work

Example 1: Swap → Stake (Lido stETH)

Example 2: Swap → Bridge (Across Protocol)

Example 3: Swap → Vault Deposit (ERC-4626)

Key Considerations

Gas Limits

Amount Handling

Failure Modes

Next Steps