Quotes & swaps

Use the Doppler SDK to discover a pool and quote a swap. Then pass the resulting pool, direction, and amounts to Uniswap's Universal Router SDK to construct and execute the transaction.

This guide focuses on the information Doppler provides for:

• Dynamic auctions

• Multicurve

• Multicurve Rehype

All three are Uniswap V4 pools. They use the same quoting API but expose their initialized PoolKey differently.

Install

pnpm add @whetstone-research/doppler-sdk viem

Set up the SDK

Only a public client is required to discover pools and request quotes:

import {
  DopplerSDK,
  getAddresses,
} from '@whetstone-research/doppler-sdk/evm'
import { createPublicClient, http } from 'viem'
import { base } from 'viem/chains'

const publicClient = createPublicClient({
  chain: base,
  transport: http(rpcUrl),
})

const sdk = new DopplerSDK({
  publicClient,
  chainId: base.id,
})

const addresses = getAddresses(base.id)

Use addresses.universalRouter when executing the swap. It is the Doppler-compatible Universal Router for the selected chain.

Use Universal Router version:

• 2.1.1 on Robinhood (chain ID 4663)

• 2.0 on every other supported network

Do not substitute a same-chain Universal Router from another address registry. Each Universal Router deployment is connected to a specific V4 PoolManager. Another router on the same chain may use a different PoolManager, where the Doppler pool is not initialized.

Get the V4 PoolKey

The PoolKey contains the exact currencies, fee configuration, tick spacing, and hook address of an initialized V4 pool. Use the key returned from onchain state without reconstructing or modifying it.

Multicurve and Multicurve Rehype

Look up either pool type by its Doppler asset address:

const pool = await sdk.getMulticurvePool(assetAddress)
const poolState = await pool.getState()

const poolKey = poolState.poolKey

For a buy, the input is normally the pool's numeraire:

const currencyInAddress = poolState.numeraire

For a sell, the input is the Doppler asset:

const currencyInAddress = poolState.asset

Use poolState.poolKey unchanged for both Multicurve and Multicurve Rehype pools.

Dynamic auctions

A Dynamic auction stores its initialized PoolKey on its hook:

import {
  dopplerHookAbi,
  normalizePoolKey,
} from '@whetstone-research/doppler-sdk/evm'

const storedPoolKey = await publicClient.readContract({
  address: hookAddress,
  abi: dopplerHookAbi,
  functionName: 'poolKey',
})

const poolKey = normalizePoolKey(storedPoolKey)

The returned key already contains the Dynamic auction's fee flag, tick spacing, currencies, and hook address.

Determine the swap direction

Uniswap V4 uses zeroForOne to identify the input side:

• true: swap currency0 for currency1

• false: swap currency1 for currency0

Derive it from the requested input currency:

function sameAddress(left: string, right: string) {
  return left.toLowerCase() === right.toLowerCase()
}

const inputIsCurrency0 = sameAddress(
  currencyInAddress,
  poolKey.currency0,
)
const inputIsCurrency1 = sameAddress(
  currencyInAddress,
  poolKey.currency1,
)

if (!inputIsCurrency0 && !inputIsCurrency1) {
  throw new Error('Input currency is not part of this PoolKey')
}

const zeroForOne = inputIsCurrency0
const currencyOutAddress = zeroForOne
  ? poolKey.currency1
  : poolKey.currency0

V4 represents native currency as the zero address. Wrapped native currency uses its ERC-20 address.

Quote an exact-input swap

Use base units for amountIn:

const quote = await sdk.quoter.quoteExactInputV4({
  poolKey,
  zeroForOne,
  exactAmount: amountIn,
  hookData: '0x',
})

console.log('Expected output:', quote.amountOut)
console.log('Quoter gas estimate:', quote.gasEstimate)

For example, use parseUnits('1', decimals) for an ERC-20 or parseEther('0.01') for an 18-decimal native or wrapped-native input.

Select the Universal Router SDK encoding version for the current chain:

const universalRouterVersion =
  publicClient.chain.id === 4_663 ? '2.1.1' : '2.0'

The values required for a single-pool exact-input V4 swap are now:

const swapQuote = {
  poolKey,
  zeroForOne,
  currencyInAddress,
  currencyOutAddress,
  amountIn,
  amountOut: quote.amountOut,
  hookData: '0x',
  universalRouter: addresses.universalRouter,
  universalRouterVersion,
}

Apply your application's slippage policy to the quote when constructing the router transaction.

Quote an exact-output swap

To calculate the input required for an exact output:

const exactOutputQuote = await sdk.quoter.quoteExactOutputV4({
  poolKey,
  zeroForOne,
  exactAmount: amountOut,
  hookData: '0x',
})

console.log('Required input:', exactOutputQuote.amountIn)
console.log('Quoter gas estimate:', exactOutputQuote.gasEstimate)

Apply your application's slippage policy to exactOutputQuote.amountIn when determining the maximum input.

Execute with Uniswap Universal Router

Use the values above with Uniswap's official Universal Router SDK. Its documentation covers transaction construction, currency objects, Permit2 or token approvals, slippage protection, native value, simulation, and submission.

When building the transaction:

• Use addresses.universalRouter.

• Select version 2.1.1 on Robinhood (chain ID 4663).

• Select version 2.0 on every other supported network.

• Pass the exact poolKey returned by the Doppler SDK.

• Pass the derived zeroForOne value.

• Use empty hook data (0x) for these swaps.

• Simulate the final transaction before submitting it.

V2 and V3 quotes

V2 and V3 are relevant for migrated pools and older Doppler deployments. New Dynamic, Multicurve, and Multicurve Rehype integrations should use the V4 path above.

V3 exact-input quote

const quote = await sdk.quoter.quoteExactInputV3({
  tokenIn: tokenInAddress,
  tokenOut: tokenOutAddress,
  amountIn,
  fee: 3_000,
  sqrtPriceLimitX96: 0n,
})

console.log('Expected output:', quote.amountOut)

Use the initialized V3 pool's actual fee tier.

V2 exact-input quote

const amounts = await sdk.quoter.quoteExactInputV2({
  amountIn,
  path: [tokenInAddress, tokenOutAddress],
})

const amountOut = amounts.at(-1)
if (amountOut === undefined) {
  throw new Error('V2 quoter returned an empty path')
}

Use the resulting route and quote with the corresponding V2 or V3 operation in the Universal Router SDK.

Quote troubleshooting

The pool cannot be quoted. Read the PoolKey from getState() or the Dynamic hook and use it unchanged. Do not guess the fee, tick spacing, currency order, or hook address.

The quoter returns NotEnoughLiquidity. Verify currencyInAddress, zeroForOne, amount units, and current pool state. The requested amount may also be outside the pool's active liquidity.

The quote succeeds but transaction construction or execution fails. Verify that the Universal Router integration uses getAddresses(chainId).universalRouter. Use version 2.1.1 on Robinhood and version 2.0 on every other supported network. Then refer to the Universal Router SDK documentation for approvals, encoding, and execution.