> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bayex.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Uniswap V4 Integration

> How Bayex builds on Uniswap V4

# Uniswap V4 Integration

Bayex uses Uniswap V4 to provide a flexible and efficient trading environment.

## Pool Architecture

### Pool Keys

Each market in Bayex corresponds to a Pool in Uniswap V4. The `PoolKey` consists of:

* **Currency0 / Currency1**: The two outcome tokens (or one outcome token and collateral).
* **Fee**: Dynamic or static fee tier.
* **Hooks**: The address of the Bayex hook contract.

### Custom Hooks (`BayexHook`)

We deploy custom hooks to manage the lifecycle of the pools.

#### Usage

1. **Initializing Pools**: Ensures pools are initialized with the correct parameters.
2. **Swap Callbacks**: executed before and after swaps. Can be used for analytics, enforcing trading hours, or dynamic fees.

## Trading Interface

Bayex utilizes the `Quoter` contract for accurate pricing and the `UniversalRouter` (or a custom adaptation) via `V4Planner` to execute swaps.

### `V4Planner`

A helper class/utility used in the SDK to construct the encoded commands for the Universal Router.

* **`addAction`**: Adds steps like `SWAP_EXACT_IN_SINGLE`.
* **Encoding**: Handles the complex encoding required by V4's router.