Hook Permissions

Uniswap V4 hooks encode their permissions in the contract address. This page documents the HookOptions enum and all 14 hook permission types.

Import

import { HookOptions, hookFlagIndex, type HookPermissions } from '@uniswap/v4-sdk-next'

HookOptions Enum

The HookOptions enum defines all available hook permissions:

enum HookOptions {
  AfterRemoveLiquidityReturnsDelta = 'afterRemoveLiquidityReturnsDelta',
  AfterAddLiquidityReturnsDelta = 'afterAddLiquidityReturnsDelta',
  AfterSwapReturnsDelta = 'afterSwapReturnsDelta',
  BeforeSwapReturnsDelta = 'beforeSwapReturnsDelta',
  AfterDonate = 'afterDonate',
  BeforeDonate = 'beforeDonate',
  AfterSwap = 'afterSwap',
  BeforeSwap = 'beforeSwap',
  AfterRemoveLiquidity = 'afterRemoveLiquidity',
  BeforeRemoveLiquidity = 'beforeRemoveLiquidity',
  AfterAddLiquidity = 'afterAddLiquidity',
  BeforeAddLiquidity = 'beforeAddLiquidity',
  AfterInitialize = 'afterInitialize',
  BeforeInitialize = 'beforeInitialize',
}

HookPermissions Type

The HookPermissions type represents all permissions as a boolean object:

type HookPermissions = {
  [key in HookOptions]: boolean
}

Hook Flag Index

The hookFlagIndex constant maps each permission to its bit position in the hook address:

const hookFlagIndex: { [key in HookOptions]: number } = {
  afterRemoveLiquidityReturnsDelta: 0,
  afterAddLiquidityReturnsDelta: 1,
  afterSwapReturnsDelta: 2,
  beforeSwapReturnsDelta: 3,
  afterDonate: 4,
  beforeDonate: 5,
  afterSwap: 6,
  beforeSwap: 7,
  afterRemoveLiquidity: 8,
  beforeRemoveLiquidity: 9,
  afterAddLiquidity: 10,
  beforeAddLiquidity: 11,
  afterInitialize: 12,
  beforeInitialize: 13,
}

Permission Categories

Initialize Permissions

Called when a pool is initialized.

Permission	Bit	Description
`BeforeInitialize`	13	Called before pool initialization
`AfterInitialize`	12	Called after pool initialization

import { Hook, HookOptions } from '@uniswap/v4-sdk-next'
 
// Check initialize permissions
Hook.hasPermission(hookAddress, HookOptions.BeforeInitialize)
Hook.hasPermission(hookAddress, HookOptions.AfterInitialize)
 
// Or use convenience method
Hook.hasInitializePermissions(hookAddress)

Liquidity Permissions

Called during liquidity operations (mint, burn, modify).

Permission	Bit	Description
`BeforeAddLiquidity`	11	Called before adding liquidity
`AfterAddLiquidity`	10	Called after adding liquidity
`BeforeRemoveLiquidity`	9	Called before removing liquidity
`AfterRemoveLiquidity`	8	Called after removing liquidity

// Check liquidity permissions
Hook.hasPermission(hookAddress, HookOptions.BeforeAddLiquidity)
Hook.hasPermission(hookAddress, HookOptions.AfterAddLiquidity)
Hook.hasPermission(hookAddress, HookOptions.BeforeRemoveLiquidity)
Hook.hasPermission(hookAddress, HookOptions.AfterRemoveLiquidity)
 
// Or use convenience method
Hook.hasLiquidityPermissions(hookAddress)

Swap Permissions

Called during swap operations.

Permission	Bit	Description
`BeforeSwap`	7	Called before a swap
`AfterSwap`	6	Called after a swap

// Check swap permissions
Hook.hasPermission(hookAddress, HookOptions.BeforeSwap)
Hook.hasPermission(hookAddress, HookOptions.AfterSwap)
 
// Or use convenience method
Hook.hasSwapPermissions(hookAddress)

Donate Permissions

Called during donate operations (adding to pool fees without receiving LP tokens).

Permission	Bit	Description
`BeforeDonate`	5	Called before a donate
`AfterDonate`	4	Called after a donate

// Check donate permissions
Hook.hasPermission(hookAddress, HookOptions.BeforeDonate)
Hook.hasPermission(hookAddress, HookOptions.AfterDonate)
 
// Or use convenience method
Hook.hasDonatePermissions(hookAddress)

Delta Permissions

These special permissions allow hooks to modify the token amounts in operations.

Permission	Bit	Description
`BeforeSwapReturnsDelta`	3	beforeSwap can modify swap amounts
`AfterSwapReturnsDelta`	2	afterSwap can modify swap amounts
`AfterAddLiquidityReturnsDelta`	1	afterAddLiquidity can modify token amounts
`AfterRemoveLiquidityReturnsDelta`	0	afterRemoveLiquidity can modify token amounts

// Check delta permissions
Hook.hasPermission(hookAddress, HookOptions.BeforeSwapReturnsDelta)
Hook.hasPermission(hookAddress, HookOptions.AfterSwapReturnsDelta)
Hook.hasPermission(hookAddress, HookOptions.AfterAddLiquidityReturnsDelta)
Hook.hasPermission(hookAddress, HookOptions.AfterRemoveLiquidityReturnsDelta)

Computing Hook Addresses

Hook addresses must have specific bits set to enable permissions. Here's how to compute them:

import { hookFlagIndex, HookOptions } from '@uniswap/v4-sdk-next'
 
function computeHookFlags(permissions: HookOptions[]): number {
  let flags = 0
  for (const permission of permissions) {
    flags |= (1 << hookFlagIndex[permission])
  }
  return flags
}
 
// Example: Hook with beforeSwap and afterSwap
const swapHookFlags = computeHookFlags([
  HookOptions.BeforeSwap,
  HookOptions.AfterSwap
])
// Result: 0xC0 (bits 6 and 7 set)
 
// The hook address must end with these flags
// e.g., 0x000000000000000000000000000000000000C0C0

Example: Creating Permission-Aware Code

import { Pool, Hook, HookOptions, ADDRESS_ZERO } from '@uniswap/v4-sdk-next'
 
async function getSwapQuote(pool: Pool, inputAmount: CurrencyAmount) {
  // Check if the hook affects swap calculations
  if (pool.hooks !== ADDRESS_ZERO) {
    const hasSwapHooks = Hook.hasSwapPermissions(pool.hooks)
    const hasDeltaHooks =
      Hook.hasPermission(pool.hooks, HookOptions.BeforeSwapReturnsDelta) ||
      Hook.hasPermission(pool.hooks, HookOptions.AfterSwapReturnsDelta)
 
    if (hasSwapHooks || hasDeltaHooks) {
      throw new Error(
        'Cannot compute quote for pools with swap hooks. ' +
        'Use an on-chain quoter instead.'
      )
    }
  }
 
  // Safe to compute quote off-chain
  return pool.getOutputAmount(inputAmount)
}

Permission Bit Layout

The last 14 bits of a hook address determine its permissions:

Address: 0x...............XXXX
                          ^^^^
                          |||\- bits 0-3: Delta permissions
                          ||\-- bits 4-5: Donate permissions
                          |\--- bits 6-7: Swap permissions
                          \---- bits 8-13: Liquidity & Initialize permissions

Visual representation of bits:

Bit 13: beforeInitialize
Bit 12: afterInitialize
Bit 11: beforeAddLiquidity
Bit 10: afterAddLiquidity
Bit 9:  beforeRemoveLiquidity
Bit 8:  afterRemoveLiquidity
Bit 7:  beforeSwap
Bit 6:  afterSwap
Bit 5:  beforeDonate
Bit 4:  afterDonate
Bit 3:  beforeSwapReturnsDelta
Bit 2:  afterSwapReturnsDelta
Bit 1:  afterAddLiquidityReturnsDelta
Bit 0:  afterRemoveLiquidityReturnsDelta

Common Permission Combinations

Use Case	Hex Suffix	Permissions
No hooks	`0x0000`	None
Swap monitoring	`0x00C0`	beforeSwap, afterSwap
Fee taking	`0x00C4`	beforeSwap, afterSwap, afterSwapReturnsDelta
Liquidity management	`0x0F00`	All liquidity hooks
Full control	`0x3FFF`	All permissions