# Integration Guide

Everything you need to integrate Biscotti: quoting, swapping, reading pool
state and tracking farm rewards. Examples use [viem](https://viem.sh), but any
EVM tooling works. Addresses are in [Contract Addresses](/developers/addresses);
minimal ABIs in [ABIs](/developers/abis).

## Setup

:::code-group
```ts [client.ts (viem)]
import { createPublicClient, defineChain, http } from 'viem'

export const arcTestnet = defineChain({
  id: 5042002,
  name: 'ARC Testnet',
  nativeCurrency: { name: 'USD Coin', symbol: 'USDC', decimals: 18 },
  rpcUrls: { default: { http: [process.env.ARC_RPC_URL!] } },
})

export const client = createPublicClient({ chain: arcTestnet, transport: http() })
```

```bash [foundry (cast)]
export RPC_URL=<arc-testnet-rpc>
export CHAIN_ID=5042002
```
:::

## Quoting

### V3 quote (QuoterV2)

`QuoterV2` simulates the swap — always call it with `eth_call`, never
on-chain:

```ts
const { result } = await client.simulateContract({
  address: QUOTER_V2,
  abi: quoterV2Abi,
  functionName: 'quoteExactInputSingle',
  args: [{
    tokenIn: USDC,
    tokenOut: EURC,
    amountIn: parseUnits('1000', 6),
    fee: 500,
    sqrtPriceLimitX96: 0n,
  }],
})
const [amountOut] = result
```

### Stable quote (get\_dy)

```ts
const amountOut = await client.readContract({
  address: STABLE_POOL_USDC_EURC,
  abi: stableSwapPoolAbi,
  functionName: 'get_dy',
  args: [0n, 1n, parseUnits('1000', 6)], // coin i → coin j
})
```

Compare both quotes (and multi-hop paths) and route accordingly — this is
exactly what the app's smart-router package does before encoding a
[Smart Router](/smart-router) transaction.

## Swapping

```ts
// One-time ERC-20 approval to the Smart Router
await walletClient.writeContract({
  address: USDC, abi: erc20Abi,
  functionName: 'approve', args: [SMART_ROUTER, maxUint256],
})

// Single V3 hop
await walletClient.writeContract({
  address: SMART_ROUTER,
  abi: smartRouterAbi,
  functionName: 'exactInputSingle',
  args: [{
    tokenIn: USDC, tokenOut: EURC, fee: 500,
    recipient: account.address,
    amountIn: parseUnits('1000', 6),
    amountOutMinimum: applySlippage(quote, 50), // 0.5%
    sqrtPriceLimitX96: 0n,
  }],
})
```

For split/mixed routes, encode multiple legs into
`multicall(deadline, bytes[])` — full example in
[Smart Router](/smart-router#integration-example).

## Reading pool state

:::code-group
```ts [V3 pool]
const [sqrtPriceX96, tick] = await client.readContract({
  address: POOL, abi: v3PoolAbi, functionName: 'slot0',
})
// price(token1/token0) = (sqrtPriceX96 / 2^96)^2, adjusted for decimals
```

```ts [Stable pool]
const virtualPrice = await client.readContract({
  address: STABLE_POOL, abi: stableSwapPoolAbi,
  functionName: 'get_virtual_price',
}) // 1e18 scale, only increases
```
:::

## Tracking farm rewards

```ts
// Classic farm — pending BSCT
const pending = await client.readContract({
  address: MASTERCHEF_ERC20, abi: masterChefErc20Abi,
  functionName: 'pendingBsctt', args: [0n, user],
})

// V3 farm — all staked positions, then pending per position
const tokenIds = await client.readContract({
  address: MASTERCHEF_V3, abi: masterChefV3Abi,
  functionName: 'getUserTokenIds', args: [user],
})
const pendingV3 = await client.readContract({
  address: MASTERCHEF_V3, abi: masterChefV3Abi,
  functionName: 'pendingBsctt', args: [tokenIds[0]],
})
```

## Batch reads

Use the deployed `UniswapInterfaceMulticall`
(`0x337361Dd8D8Ee27Ab5EfFec69412AC8B080d704a`) or viem's built-in
`multicall` to aggregate reads in one RPC round-trip.

## Historical data

For volume, TVL and price history, query the
[analytics subgraphs](/analytics#subgraphs) instead of replaying events
yourself.