# Pair Address

## 🔍 Getting a Pair Address

To interact with a liquidity pool on Zealous Swap, you first need the address of the pair contract that manages the pool between two tokens. There are two ways to get this address:

***

### ✅ Method 1: On-Chain via `getPair`

The simplest way is to use the factory contract’s `getPair()` function:

```solidity
address pair = IZealousSwapFactory(factory).getPair(tokenA, tokenB);
```

* If the pair **exists**, it returns the pair contract address.
* If the pair **does not exist**, it returns `address(0)`.

> Note: The tokens must be passed in **any order**. The factory handles the sorting internally.

***

### ⚡ Method 2: Off-Chain via `CREATE2` (No RPC Needed)

Zealous Swap uses `CREATE2` to deploy pairs at deterministic addresses. This means you can **pre-compute** a pair’s address without interacting with the blockchain.

To do this, you’ll need:

* `factory`: the Zealous Factory address
* `token0`, `token1`: the two token addresses, sorted in ascending order
* `initCodeHash`: the hash of the pair creation bytecode used by the factory

***

#### 🧮 Solidity Example

<pre class="language-solidity"><code class="lang-solidity"><strong>address factory = 0xZealousSwapFactoryAddress;
</strong>address token0 = 0xCAFE...; // lower address
address token1 = 0xF00D...; // higher address

bytes32 salt = keccak256(abi.encodePacked(token0, token1));
bytes32 initCodeHash = hex'...'; // Zealous Swap Pair init code hash

address pair = address(uint160(uint(keccak256(abi.encodePacked(
  hex'ff',
  factory,
  salt,
  initCodeHash
)))));
</code></pre>

Make sure `token0 < token1`. If not, sort them before hashing.

***

### 🔐 Pair Sorting Logic

Zealous Swap enforces a consistent token order in every pair. Before calling `keccak256(abi.encodePacked(token0, token1))`, you must ensure:

```solidity
(token0 < token1)
```

This guarantees consistent pair addresses across clients and tools.

***

### ✅ Summary

| Method      | Lookup   | Requires RPC | Use Case                 |
| ----------- | -------- | ------------ | ------------------------ |
| `getPair()` | On-chain | ✅ Yes        | In-contract logic        |
| `CREATE2`   | Offline  | ❌ No         | Precomputing or indexing |