swap-integration

What this skill does

# Swap Integration

Integrate PancakeSwap swaps into frontends, backends, and smart contracts.

## Quick Decision Guide

| Building...                                | Use This Method                                                                |
| ------------------------------------------ | ------------------------------------------------------------------------------ |
| Quick quote or prototype                   | PancakeSwap Routing API (Method 1)                                             |
| Frontend with React/Next.js                | Smart Router SDK + Universal Router (Method 2)                                 |
| Backend script or trading bot              | Smart Router SDK + Universal Router (Method 2)                                 |
| Simple V2 swap, smart contract             | Direct V2 Router contract calls (Method 3)                                     |
| Need exact Universal Router encoding       | Universal Router SDK directly (Method 2)                                       |
| Swap through Infinity (v4) CL or Bin pools | Routing API (Method 1) or Smart Router SDK with Infinity pool types (Method 2) |

### Protocol Types

| Protocol     | Description                                                                                      | Fee Tiers (bps)         | Chains        |
| ------------ | ------------------------------------------------------------------------------------------------ | ----------------------- | ------------- |
| V2           | Classic AMM (xy=k), constant product formula                                                     | 25 (0.25%)              | BSC only      |
| V3           | Concentrated liquidity (Uniswap V3-compatible)                                                   | 1, 5, 25, 100 (0.01–1%) | All chains    |
| StableSwap   | Low-slippage for correlated/pegged assets                                                        | 1, 4 (0.01–0.04%)       | BSC only      |
| Infinity CL  | Concentrated liquidity in the v4 singleton PoolManager; supports hooks for custom logic          | Same tiers as V3        | BSC, Base     |
| Infinity Bin | Fixed-price-bin liquidity (similar to Trader Joe v2); tight ranges, predictable bin-level prices | Configurable            | BSC, Base     |
| Mixed        | Split route across any combination of the above protocols                                        | N/A (composite)         | BSC primarily |

## Supported Chains

| Chain                   | Chain ID | V2  | V3  | StableSwap | Infinity CL | Infinity Bin | RPC                                                                      |
| ----------------------- | -------- | --- | --- | ---------- | ----------- | ------------ | ------------------------------------------------------------------------ |
| BNB Smart Chain         | 56       | ✅  | ✅  | ✅         | ✅          | ✅           | `https://bsc-dataseed1.binance.org`                                      |
| BNB Smart Chain Testnet | 97       | ✅  | ❌  | ❌         | ❌          | ❌           | `https://bsc-testnet-rpc.publicnode.com or https://bsc-testnet.drpc.org` |
| Ethereum                | 1        | ❌  | ✅  | ❌         | ❌          | ❌           | `https://cloudflare-eth.com`                                             |
| Arbitrum One            | 42161    | ❌  | ✅  | ❌         | ❌          | ❌           | `https://arb1.arbitrum.io/rpc`                                           |
| Base                    | 8453     | ❌  | ✅  | ❌         | ✅          | ✅           | `https://mainnet.base.org`                                               |
| Polygon                 | 137      | ❌  | ✅  | ❌         | ❌          | ❌           | `https://polygon-rpc.com`                                                |
| zkSync Era              | 324      | ❌  | ✅  | ❌         | ❌          | ❌           | `https://mainnet.era.zksync.io`                                          |
| Linea                   | 59144    | ❌  | ✅  | ❌         | ❌          | ❌           | `https://rpc.linea.build`                                                |
| opBNB                   | 204      | ❌  | ✅  | ❌         | ❌          | ❌           | `https://opbnb-mainnet-rpc.bnbchain.org`                                 |

> **For testing**: Use **BSC Testnet (chain ID 97)**. Get free testnet BNB from <https://testnet.bnbchain.org/faucet-smart>.
> The Smart Router SDK does not index testnet pools — use **Method 3 (Direct V2 Router)** on testnet.

## Key Token Addresses

### BSC Mainnet (Chain ID: 56)

| Token | Address                                      |
| ----- | -------------------------------------------- |
| WBNB  | `0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c` |
| BUSD  | `0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56` |
| USDT  | `0x55d398326f99059fF775485246999027B3197955` |
| USDC  | `0x8AC76a51cc950d9822D68b83fE1Ad97B32Cd580d` |
| CAKE  | `0x0E09FaBB73Bd3Ade0a17ECC321fD13a19e81cE82` |
| ETH   | `0x2170Ed0880ac9A755fd29B2688956BD959F933F8` |
| BTCB  | `0x7130d2A12B9BCbFAe4f2634d864A1Ee1Ce3Ead9c` |

### BSC Testnet (Chain ID: 97)

| Token    | Address                                      | Notes               |
| -------- | -------------------------------------------- | ------------------- |
| WBNB     | `0xae13d989daC2f0dEbFf460aC112a837C89BAa7cd` |                     |
| CAKE     | `0xFa60D973f7642b748046464E165A65B7323b0C73` |                     |
| BUSD     | `0xeD24FC36d5Ee211Ea25A80239Fb8C4Cfd80f12Ee` |                     |
| V2Router | `0x9Ac64Cc6e4415144C455BD8E4837Fea55603e5c3` | PancakeSwap testnet |

### Universal Router Addresses

| Chain           | Chain ID | Universal Router Address                     |
| --------------- | -------- | -------------------------------------------- |
| BNB Smart Chain | 56       | `0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD` |
| Ethereum        | 1        | `0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD` |
| Arbitrum        | 42161    | `0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD` |
| Base            | 8453     | `0x198EF79F1F515F02dFE9e3115eD9fC07183f02fC` |
| Polygon         | 137      | `0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD` |
| zkSync Era      | 324      | `0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD` |
| Linea           | 59144    | `0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD` |
| opBNB           | 204      | `0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD` |

---

## Method 1: PancakeSwap Routing API (Simplest)

Best for: Quick quotes, prototypes, and situations where you don't want to manage on-chain pool data yourself. No SDK installation required.

**Base URL**: `https://router.pancakeswap.finance/v0/quote`

### Get a Quote

```bash
# Exact input: 1 BNB → CAKE on BSC
curl -s "https://router.pancakeswap.finance/v0/quote?\
tokenInAddress=BNB\
&tokenInChainId=56\
&tokenOutAddress=0x0E09FaBB73Bd3Ade0a17ECC321fD13a19e81cE82\
&tokenOutChainId=56\
&amount=1000000000000000000\
&type=exactIn\
&maxHops=3\
&maxSplits=4" | jq '{
  amountOut: .trade.outputAmount,
  priceImpact: .trade.priceImpact,
  route: [.trade.routes[].type]
}'
```

### API Parameters

| Parameter         | Type   | Description                                         |
| ----------------- | ------ | --------------------------------------------------- |
| `tokenInAddress`  | string | Input token address or `"BNB"` / `"ETH"` for native |
| `tokenInChainId`  | number | Input chain ID                                      |
| `tokenOutAddress` | string | Output token address                                |
| `tokenOutChainId` | number | Output chain ID                                     |
| `amount`          | string | Amount in raw units (wei for 18-decimal tokens)     |
| `type`            | string | `"exactIn"` or `"exactOut"`                         |
| `maxHops`         | number | Max hops per route (default: 3)                     |
| `maxSplits`       | number | Max route splits (default: 4)                       |

> **Infinity (v4) support**: The Routing API automatica