Few Hook Contracts

Few Protocol provides specialized hook contracts for v4 pools that connect underlying assets with Few wrapped tokens. These hooks are designed to let pool creators and integrators work with user-facing assets such as ETH, USDC, DAI, and USDT while the pool can still use the corresponding Few wrapped asset where appropriate.

Overview

Few hooks are intended to simplify wrapped-token pool integrations by handling token conversion at the hook layer.

• Automatic wrapping before liquidity is added to supported pools
• Swap flows that can accept underlying assets for wrapped-token pools
• Token-specific handling for native ETH and non-standard ERC20s such as USDT
• Reusable hook contracts that can be attached to v4 pools through the hooks field on PoolKey

Available Hook Types

Standard ERC20 Hooks

For standard ERC20 integrations, Few provides token-specific hooks such as FewUSDCHook, FewDAIHook, FewUNIHook, FewWBTCHook, and FewCBBTCHook.

These hooks are designed for assets that follow standard ERC20 transfer and approval behavior and typically support:

• 1:1 wrapping and unwrapping between the underlying token and its Few wrapped representation
• Pool creation against Few wrapped assets
• Automated conversion during liquidity and swap flows

FewETHHook

FewETHHook is intended for pools that integrate ETH, WETH, or fwWETH.

This hook is optimized for native ETH flows and can help:

• Accept native ETH in user-facing interactions
• Wrap or unwrap between ETH and the Few wrapped ETH representation
• Reduce custom integration logic for ETH-based pools

FewUSDTHook

FewUSDTHook is intended for USDT integrations, where approval behavior differs from many standard ERC20 tokens.

This hook is useful when you need:

• USDT-compatible approval handling
• Safer integration with non-standard token behavior
• A dedicated hook path instead of reusing a standard ERC20 flow

Mainnet Hook Deployments

The following hook contracts are currently published for Ethereum mainnet:

Pair	Hook Contract	Ethereum Mainnet Address	Pool ID
ETH / fwWETH	FewETHHook	0x044301939dEB7ca53C4733dd4D9B3bc5Ea0c6888	0x7a5a8f5a36a6a2e9961caf6bb047a5a7580d0fe16a532aad93efc596028dfa54
UNI / fwUNI	FewUNIHook	0x4b3E2a8cF36c7EB0fBa2A5b39B20c896C6f22888	0x301d41ff23b73b209ab2b1112f4effd0d8ff978ec29d743c1431463f84cbec24
WBTC / fwWBTC	FewWBTCHook	0x0FE942AFdb2F51e25cbf892aAd175C6A574F2888	0x18605c7a76101aeccc414cc300dd5e5ae44b30d6c247ba164ccd88952c259735
USDC / fwUSDC	FewUSDCHook	0x4b2EB653D13E6C9ac5A0A01fDe22F2C8d6592888	0x5837e6b4fd4b8193f2f7a8b4490c0f154344bb9a52b36a885578ff6d3193fc47
DAI / fwDAI	FewDAIHook	0x85B648a64Aed6307D5d5Ce26e6Ae086C17Bde888	0xf906beb74154ca4d057b7079c90eb1044efaf40ef468e62ec983930cf80a1e2b
USDT / fwUSDT	FewUSDTHook	0xBAdF77d50478b4432eF1F243B9C0bC7869486888	0x7db868544c8f7f6ddb107c7749c94f03c9e0155f2138aef3f8a020e4a469d95a
cbBTC / fwcbBTC	FewCBBTCHook	0x8347b7A3807C681513D2B51b8223e59aA16a2888	0x8f8b0b21fb429ffb5210f2bf0f8b7cb267b944a0c61beaae35f20f6839c0f33b
weETH / fwweETH	FewweETHHook	0x877323adBf747f85eb8D182D42f01f34A5492888	0x6933dfbf7441cc4ee4439843fdd464e215a6c90f07c5a769198e2a047f1f3f3e
wstETH / fwwstETH	FewwstETHHook	0x75ae0292E8AD3ab60B9A1A7B3046d3F4Abdfa888	0xe7c2f30fd89238331b0e3e6ac6351578d5e3091b7839eff321c29cf88e17274e

For the broader Ring Swap and Few deployment list, see Ring Protocol Contracts.

For complete PoolKey data, initialization transactions, and aggregator routing requirements, see FewToken Liquidity and Aggregator Integration.

How Few Hooks Work

1. Pool Initialization

When a v4 pool is created, the hook contract is assigned through the hooks field of PoolKey. This binds the pool to the hook lifecycle configured by that hook's permission flags.

2. Liquidity Provision

When liquidity is added with an underlying asset, the hook can validate the pool configuration and convert the deposited token into the Few wrapped representation expected by the pool.

3. Swaps

During swaps, the hook can run pre-swap conversion logic so users can interact with the underlying asset while the pool continues to account for the wrapped asset path.

4. Liquidity Removal

When liquidity is removed, the hook can unwrap the resulting wrapped balance back into the underlying asset expected by the integrator or end user.

Hook Permissions

Few hook integrations rely on standard v4 hook permissions. The exact combination depends on the hook implementation, but the most relevant permissions are:

Flag	Purpose
BEFORE_INITIALIZE_FLAG	Validates pool setup before first initialization
BEFORE_ADD_LIQUIDITY_FLAG	Wraps or validates assets before liquidity is added
BEFORE_SWAP_FLAG	Performs pre-swap token conversion and checks
BEFORE_SWAP_RETURNS_DELTA_FLAG	Returns swap deltas needed for conversion-aware flows

To understand how hook permissions are encoded in contract addresses, see Hook Deployment and IHooks.

Integration Notes

For Pool Creators

• Choose the hook that matches the token behavior of your pool
• Set the hook address in the hooks field when building the PoolKey
• Initialize and test the pool with the exact underlying and wrapped token pairing you expect to support

For Frontend and SDK Integrators

• Continue to build around standard v4 pool creation and swap flows
• Display the underlying asset to users when the hook abstracts wrapping behavior
• Handle reverts from hook validation in the same way you handle other pool initialization or swap errors

Example Pool Initialization

PoolKey memory key = PoolKey({
    currency0: Currency.wrap(USDC_ADDRESS),
    currency1: Currency.wrap(FW_USDC_ADDRESS),
    fee: 3000,
    tickSpacing: 60,
    hooks: IHooks(FEW_USDC_HOOK_ADDRESS)
});

poolManager.initialize(key, SQRT_PRICE_1_1);

The hook address selected in hooks determines which lifecycle callbacks the v4 hook system will invoke for that pool.