Content-Type: application/json
x-api-key: <your-api-key>
x-universal-router-version: 2.0
x-agent-info: {"integration_name":"swap-integration","decision_origin":"<human_mediated|autonomous>","version":"1.5.0"}

1. POST /check_approval  -> Check if token is approved
2. POST /quote           -> Get executable quote with routing
3. POST /swap            -> Get transaction to sign and submit

npm install @uniswap/universal-router-sdk @uniswap/sdk-core @uniswap/v3-sdk

import { SwapRouter } from '@uniswap/universal-router-sdk';
const { calldata, value } = SwapRouter.swapCallParameters(trade, options);

POST /check_approval

{
  "walletAddress": "0x...",
  "token": "0x...",
  "amount": "1000000000",
  "chainId": 1
}

{
  "approval": {
    "to": "0x...",
    "from": "0x...",
    "data": "0x...",
    "value": "0",
    "chainId": 1
  }
}

POST /quote

{
  "swapper": "0x...",
  "tokenIn": "0x...",
  "tokenOut": "0x...",
  "tokenInChainId": "1",
  "tokenOutChainId": "1",
  "amount": "1000000000000000000",
  "type": "EXACT_INPUT",
  "slippageTolerance": 0.5,
  "routingPreference": "BEST_PRICE"
}

{
  "routing": "CLASSIC",
  "quote": {
    "input": { "token": "0x...", "amount": "1000000000000000000" },
    "output": { "token": "0x...", "amount": "999000000" },
    "slippage": 0.5,
    "route": [],
    "gasFee": "5000000000000000",
    "gasFeeUSD": "0.01",
    "gasUseEstimate": "150000"
  },
  "permitData": null
}

{
  "routing": "DUTCH_V2",
  "quote": {
    "orderInfo": {
      "reactor": "0x...",
      "swapper": "0x...",
      "nonce": "...",
      "deadline": 1772031054,
      "cosigner": "0x...",
      "input": {
        "token": "0x...",
        "startAmount": "1000000000000000000",
        "endAmount": "1000000000000000000"
      },
      "outputs": [
        {
          "token": "0x...",
          "startAmount": "999000000",
          "endAmount": "994000000",
          "recipient": "0x..."
        }
      ],
      "chainId": 1
    },
    "encodedOrder": "0x...",
    "orderHash": "0x..."
  },
  "permitData": { "domain": {}, "types": {}, "values": {} }
}

POST /swap

// CORRECT: Spread the quote response, strip null fields
const quoteResponse = await fetchQuote(params);
// Always strip permitData/permitTransaction — handle them explicitly by routing type
const { permitData, permitTransaction, ...cleanQuote } = quoteResponse;
const swapRequest: Record<string, unknown> = { ...cleanQuote };
const isUniswapX =
  quoteResponse.routing === 'DUTCH_V2' ||
  quoteResponse.routing === 'DUTCH_V3' ||
  quoteResponse.routing === 'PRIORITY';
if (isUniswapX) {
  // UniswapX: signature only — permitData must NOT go to /swap
  if (permit2Signature) swapRequest.signature = permit2Signature;
} else {
  // CLASSIC: both signature and permitData, or neither
  if (permit2Signature && permitData && typeof permitData === 'object') {
    swapRequest.signature = permit2Signature;
    swapRequest.permitData = permitData;
  }
}

{
  "swap": {
    "to": "0x...",
    "from": "0x...",
    "data": "0x...",
    "value": "0",
    "chainId": 1,
    "gasLimit": "250000"
  }
}

function validateSwapResponse(response: SwapResponse): void {
  if (!response.swap?.data || response.swap.data === '' || response.swap.data === '0x') {
    throw new Error('swap.data is empty - quote may have expired');
  }
  if (!isAddress(response.swap.to) || !isAddress(response.swap.from)) {
    throw new Error('Invalid address in swap response');
  }
}

// WRONG - causes "quote does not match any of the allowed types"
const badRequest = {
  quote: quoteResponse, // Don't wrap!
  signature: '0x...',
};
// CORRECT - spread the quote response
const goodRequest = {
  ...quoteResponse,
  signature: '0x...', // Only if using Permit2
};

function prepareSwapRequest(quoteResponse: QuoteResponse, signature?: string): object {
  // Always strip permitData and permitTransaction from the spread — handle them explicitly
  const { permitData, permitTransaction, ...cleanQuote } = quoteResponse;
  const request: Record<string, unknown> = { ...cleanQuote };
  // UniswapX (DUTCH_V2, DUTCH_V3, PRIORITY): permitData is for LOCAL signing only.
  // The /swap body must NOT include permitData — the order is encoded in
  // quote.encodedOrder. Only the signature is needed.
  const isUniswapX =
    quoteResponse.routing === 'DUTCH_V2' ||
    quoteResponse.routing === 'DUTCH_V3' ||
    quoteResponse.routing === 'PRIORITY';
  if (isUniswapX) {
    if (signature) request.signature = signature;
  } else {
    // CLASSIC: both signature and permitData required together, or both omitted.
    // The Universal Router contract needs permitData to verify the Permit2
    // authorization on-chain.
    if (signature && permitData && typeof permitData === 'object') {
      request.signature = signature;
      request.permitData = permitData;
    }
  }
  return request;
}

import { isAddress, isHex } from 'viem';
function validateSwapBeforeBroadcast(swap: SwapTransaction): void {
  // 1. data must be non-empty hex
  if (!swap.data || swap.data === '' || swap.data === '0x') {
    throw new Error('swap.data is empty - this will revert on-chain. Re-fetch the quote.');
  }
  if (!isHex(swap.data)) {
    throw new Error('swap.data is not valid hex');
  }
  // 2. Addresses must be valid
  if (!isAddress(swap.to)) {
    throw new Error('swap.to is not a valid address');
  }
  if (!isAddress(swap.from)) {
    throw new Error('swap.from is not a valid address');
  }
  // 3. Value must be present (can be "0" for non-ETH swaps)
  if (swap.value === undefined || swap.value === null) {
    throw new Error('swap.value is missing');
  }
}

npm install buffer

// src/main.tsx or src/index.tsx
import { Buffer } from 'buffer';
globalThis.Buffer = Buffer;
// Then your other imports
import React from 'react';
import { WagmiProvider } from 'wagmi';
// ...

export default defineConfig({
  define: {
    global: 'globalThis',
  },
  optimizeDeps: {
    include: ['buffer'],
  },
  resolve: {
    alias: {
      buffer: 'buffer',
    },
  },
});

export default defineConfig({
  server: {
    proxy: {
      '/api/uniswap': {
        target: 'https://trade-api.gateway.uniswap.org/v1',
        changeOrigin: true,
        rewrite: (path) => path.replace(/^\/api\/uniswap/, ''),
      },
    },
  },
});

{
  "rewrites": [
    {
      "source": "/api/uniswap/:path*",
      "destination": "https://trade-api.gateway.uniswap.org/v1/:path*"
    }
  ]
}

/api/uniswap/* https://trade-api.gateway.uniswap.org/v1/:splat 200

module.exports = {
  async rewrites() {
    return [
      {
        source: '/api/uniswap/:path*',
        destination: 'https://trade-api.gateway.uniswap.org/v1/:path*',
      },
    ];
  },
};

type ClassicQuoteResponse = {
  routing: 'CLASSIC' | 'WRAP' | 'UNWRAP';
  quote: {
    input: { token: string; amount: string };
    output: { token: string; amount: string };
    slippage: number;
    route: unknown[];
    gasFee: string;
    gasFeeUSD: string;
    gasUseEstimate: string;
  };
  permitData: Record<string, unknown> | null;
};
type DutchOrderOutput = {
  token: string;
  startAmount: string;
  endAmount: string;
  recipient: string;
};
type UniswapXQuoteResponse = {
  routing: 'DUTCH_V2' | 'DUTCH_V3' | 'PRIORITY';
  quote: {
    orderInfo: {
      outputs: DutchOrderOutput[];
      input: { token: string; startAmount: string; endAmount: string };
      deadline: number;
      nonce: string;
    };
    encodedOrder: string;
    orderHash: string;
  };
  // EIP-712 typed data — sign locally, do NOT send to /swap
  permitData: Record<string, unknown> | null;
};
type QuoteResponse = ClassicQuoteResponse | UniswapXQuoteResponse;
// Type guard for routing-aware logic
function isUniswapXQuote(q: QuoteResponse): q is UniswapXQuoteResponse {
  return q.routing === 'DUTCH_V2' || q.routing === 'DUTCH_V3' || q.routing === 'PRIORITY';
}
// Reading the output amount by routing type
function getOutputAmount(q: QuoteResponse): string {
  if (isUniswapXQuote(q)) {
    const firstOutput = q.quote.orderInfo.outputs[0];
    if (!firstOutput) throw new Error('UniswapX quote has no outputs');
    // startAmount = best-case fill; endAmount = floor after auction decay
    return firstOutput.startAmount;
  }
  return q.quote.output.amount;
}

function execute(
    bytes calldata commands,
    bytes[] calldata inputs,
    uint256 deadline
) external payable;

import { SwapRouter, UniswapTrade } from '@uniswap/universal-router-sdk'
import { TradeType } from '@uniswap/sdk-core'
// Build trade using v3-sdk or router-sdk
const trade = new RouterTrade({
  v3Routes: [...],
  tradeType: TradeType.EXACT_INPUT
})
// Get calldata for Universal Router
const { calldata, value } = SwapRouter.swapCallParameters(trade, {
  slippageTolerance: new Percent(50, 10000), // 0.5%
  recipient: walletAddress,
  deadline: Math.floor(Date.now() / 1000) + 1200 // 20 min
})
// Send transaction
const tx = await wallet.sendTransaction({
  to: UNIVERSAL_ROUTER_ADDRESS,
  data: calldata,
  value
})

import { getContract, maxUint256, type Address } from 'viem';
const PERMIT2_ADDRESS = '0x000000000022D473030F116dDEE9F6B43aC78BA3' as const;
// Check if Permit2 approval exists
const allowance = await publicClient.readContract({
  address: PERMIT2_ADDRESS,
  abi: permit2Abi,
  functionName: 'allowance',
  args: [userAddress, tokenAddress, spenderAddress],
});
// If not approved, user must approve Permit2 first
if (allowance.amount < requiredAmount) {
  const hash = await walletClient.writeContract({
    address: tokenAddress,
    abi: erc20Abi,
    functionName: 'approve',
    args: [PERMIT2_ADDRESS, maxUint256],
  });
  await publicClient.waitForTransactionReceipt({ hash });
}
// Then sign permit for the swap
const permitSignature = await signPermit(...);

npm install @uniswap/universal-router-sdk @uniswap/router-sdk @uniswap/sdk-core @uniswap/v3-sdk viem

import { SwapRouter } from '@uniswap/universal-router-sdk';
import { Trade as RouterTrade } from '@uniswap/router-sdk';
import { TradeType, Percent } from '@uniswap/sdk-core';
import { Route as V3Route, Pool } from '@uniswap/v3-sdk';
// 1. Fetch pool data (required to construct routes)
// Using viem to read on-chain pool state:
const slot0 = await publicClient.readContract({
  address: poolAddress,
  abi: [
    {
      name: 'slot0',
      type: 'function',
      stateMutability: 'view',
      inputs: [],
      outputs: [
        { name: 'sqrtPriceX96', type: 'uint160' },
        { name: 'tick', type: 'int24' },
        { name: 'observationIndex', type: 'uint16' },
        { name: 'observationCardinality', type: 'uint16' },
        { name: 'observationCardinalityNext', type: 'uint16' },
        { name: 'feeProtocol', type: 'uint8' },
        { name: 'unlocked', type: 'bool' },
      ],
    },
  ],
  functionName: 'slot0',
});
const liquidity = await publicClient.readContract({
  address: poolAddress,
  abi: [
    {
      name: 'liquidity',
      type: 'function',
      stateMutability: 'view',
      inputs: [],
      outputs: [{ type: 'uint128' }],
    },
  ],
  functionName: 'liquidity',
});
const pool = new Pool(tokenIn, tokenOut, fee, slot0[0].toString(), liquidity.toString(), slot0[1]);
// 2. Build route and trade
const route = new V3Route([pool], tokenIn, tokenOut);
const trade = RouterTrade.createUncheckedTrade({
  route,
  inputAmount: amountIn,
  outputAmount: expectedOut,
  tradeType: TradeType.EXACT_INPUT,
});
// 3. Get calldata
const { calldata, value } = SwapRouter.swapCallParameters(trade, {
  slippageTolerance: new Percent(50, 10000), // 0.5%
  recipient: walletAddress,
  deadline: Math.floor(Date.now() / 1000) + 1800,
});
// 4. Execute with viem
const hash = await walletClient.sendTransaction({
  to: UNIVERSAL_ROUTER_ADDRESS,
  data: calldata,
  value: BigInt(value),
});

import { RoutePlanner, CommandType, ROUTER_AS_RECIPIENT } from '@uniswap/universal-router-sdk';
import { encodeRouteToPath } from '@uniswap/v3-sdk';
// Special addresses
const MSG_SENDER = '0x0000000000000000000000000000000000000001';
const ADDRESS_THIS = '0x0000000000000000000000000000000000000002';

import { RoutePlanner, CommandType } from '@uniswap/universal-router-sdk';
import { encodeRouteToPath, Route } from '@uniswap/v3-sdk';
async function swapV3Manual(route: Route, amountIn: bigint, amountOutMin: bigint) {
  const planner = new RoutePlanner();
  // Encode V3 path from route
  const path = encodeRouteToPath(route, false); // false = exactInput
  planner.addCommand(CommandType.V3_SWAP_EXACT_IN, [
    MSG_SENDER, // recipient
    amountIn, // amountIn
    amountOutMin, // amountOutMin
    path, // encoded path
    true, // payerIsUser
  ]);
  return executeRoute(planner);
}

async function swapEthToToken(route: Route, amountIn: bigint, amountOutMin: bigint) {
  const planner = new RoutePlanner();
  const path = encodeRouteToPath(route, false);
  // 1. Wrap ETH to WETH (keep in router)
  planner.addCommand(CommandType.WRAP_ETH, [ADDRESS_THIS, amountIn]);
  // 2. Swap WETH → Token (payerIsUser = false since using router's WETH)
  planner.addCommand(CommandType.V3_SWAP_EXACT_IN, [
    MSG_SENDER,
    amountIn,
    amountOutMin,
    path,
    false,
  ]);
  return executeRoute(planner, { value: amountIn });
}

async function swapTokenToEth(route: Route, amountIn: bigint, amountOutMin: bigint) {
  const planner = new RoutePlanner();
  const path = encodeRouteToPath(route, false);
  // 1. Swap Token → WETH (output to router)
  planner.addCommand(CommandType.V3_SWAP_EXACT_IN, [
    ADDRESS_THIS,
    amountIn,
    amountOutMin,
    path,
    true,
  ]);
  // 2. Unwrap WETH to ETH
  planner.addCommand(CommandType.UNWRAP_WETH, [MSG_SENDER, amountOutMin]);
  return executeRoute(planner);
}

async function swapWithFee(route: Route, amountIn: bigint, feeRecipient: Address, feeBips: number) {
  const planner = new RoutePlanner();
  const path = encodeRouteToPath(route, false);
  const outputToken = route.output.wrapped.address;
  // Swap to router (ADDRESS_THIS)
  planner.addCommand(CommandType.V3_SWAP_EXACT_IN, [ADDRESS_THIS, amountIn, 0n, path, true]);
  // Pay fee portion (e.g., 30 bips = 0.3%)
  planner.addCommand(CommandType.PAY_PORTION, [outputToken, feeRecipient, feeBips]);
  // Sweep remainder to user
  planner.addCommand(CommandType.SWEEP, [outputToken, MSG_SENDER, 0n]);
  return executeRoute(planner);
}

import { UNIVERSAL_ROUTER_ADDRESS } from '@uniswap/universal-router-sdk';
const ROUTER_ABI = [
  {
    name: 'execute',
    type: 'function',
    stateMutability: 'payable',
    inputs: [
      { name: 'commands', type: 'bytes' },
      { name: 'inputs', type: 'bytes[]' },
      { name: 'deadline', type: 'uint256' },
    ],
    outputs: [],
  },
] as const;
async function executeRoute(planner: RoutePlanner, options?: { value?: bigint }) {
  const deadline = BigInt(Math.floor(Date.now() / 1000) + 1800);
  const routerAddress = UNIVERSAL_ROUTER_ADDRESS('2.0', 1); // version, chainId
  const { request } = await publicClient.simulateContract({
    address: routerAddress,
    abi: ROUTER_ABI,
    functionName: 'execute',
    args: [planner.commands, planner.inputs, deadline],
    account,
    value: options?.value ?? 0n,
  });
  return walletClient.writeContract(request);
}

import { isAddress, isHex } from 'viem';
import { useWalletClient } from 'wagmi';
// In browser apps, use your CORS proxy path instead (see CORS Proxy Configuration)
// e.g., const API_URL = '/api/uniswap';
const API_URL = 'https://trade-api.gateway.uniswap.org/v1';
// REQUIRED: define decision_origin yourself — 'human_mediated' (a human reviews/approves
// each action before it executes) or 'autonomous' (no per-action human approval).
// See Agent Attribution above. There is no default — you must choose.
declare const DECISION_ORIGIN: 'human_mediated' | 'autonomous';
const AGENT_INFO = JSON.stringify({
  integration_name: 'swap-integration',
  decision_origin: DECISION_ORIGIN,
  version: '1.5.0',
});
function useSwap() {
  const { data: walletClient } = useWalletClient();
  const [quoteResponse, setQuoteResponse] = useState(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState(null);
  const getQuote = async (params) => {
    setLoading(true);
    setError(null);
    try {
      const response = await fetch(`${API_URL}/quote`, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'x-api-key': API_KEY,
          'x-universal-router-version': '2.0',
          'x-agent-info': AGENT_INFO,
        },
        body: JSON.stringify(params),
      });
      const data = await response.json();
      if (!response.ok) throw new Error(data.detail || 'Quote failed');
      setQuoteResponse(data); // Store the FULL response, not just data.quote
    } catch (err) {
      setError(err.message);
    } finally {
      setLoading(false);
    }
  };
  const executeSwap = async (permit2Signature?: string) => {
    if (!quoteResponse) throw new Error('No quote available');
    // Strip null fields and spread quote response into body
    const { permitData, permitTransaction, ...cleanQuote } = quoteResponse;
    const swapRequest: Record<string, unknown> = { ...cleanQuote };
    // CRITICAL: permitData handling differs by routing type
    const isUniswapX =
      quoteResponse.routing === 'DUTCH_V2' ||
      quoteResponse.routing === 'DUTCH_V3' ||
      quoteResponse.routing === 'PRIORITY';
    if (isUniswapX) {
      // UniswapX: signature only — permitData must NOT be sent to /swap
      // (permitData is used locally to sign the order, not submitted to the API)
      if (permit2Signature) swapRequest.signature = permit2Signature;
    } else {
      // CLASSIC: both signature and permitData required together, or both omitted
      if (permit2Signature && permitData && typeof permitData === 'object') {
        swapRequest.signature = permit2Signature;
        swapRequest.permitData = permitData;
      }
    }
    const swapResponse = await fetch(`${API_URL}/swap`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'x-api-key': API_KEY,
        'x-universal-router-version': '2.0',
        'x-agent-info': AGENT_INFO,
      },
      body: JSON.stringify(swapRequest),
    });
    const data = await swapResponse.json();
    if (!swapResponse.ok) throw new Error(data.detail || 'Swap failed');
    // CRITICAL: Validate response before broadcasting
    if (!data.swap?.data || data.swap.data === '' || data.swap.data === '0x') {
      throw new Error('Empty swap data - quote may have expired. Please refresh.');
    }
    // Send transaction via wallet (walletClient from useWalletClient())
    if (!walletClient) throw new Error('Wallet not connected');
    const tx = await walletClient.sendTransaction(data.swap);
    return tx;
  };
  return { quote: quoteResponse?.quote, loading, error, getQuote, executeSwap };
}

import { getWalletClient, getPublicClient, switchChain } from '@wagmi/core';
import type { Config } from 'wagmi';
async function executeSwapTransaction(
  config: Config,
  chainId: number,
  swapTx: { to: string; data: string; value: string }
) {
  // 1. Ensure the wallet is on the correct chain
  await switchChain(config, { chainId });
  // 2. Get wallet client with explicit chainId — avoids undefined and missing chain
  const walletClient = await getWalletClient(config, { chainId });
  // 3. Execute the swap
  const hash = await walletClient.sendTransaction({
    to: swapTx.to as `0x${string}`,
    data: swapTx.data as `0x${string}`,
    value: BigInt(swapTx.value || '0'),
  });
  // 4. Wait for confirmation
  const publicClient = getPublicClient(config, { chainId });
  if (!publicClient) throw new Error(`No public client configured for chainId ${chainId}`);
  return publicClient.waitForTransactionReceipt({ hash });
}

import { createWalletClient, createPublicClient, http, isAddress, isHex, type Address } from 'viem';
import { privateKeyToAccount } from 'viem/accounts';
import { mainnet } from 'viem/chains';
const API_URL = 'https://trade-api.gateway.uniswap.org/v1';
const API_KEY = process.env.UNISWAP_API_KEY!;
// REQUIRED: define decision_origin yourself — 'human_mediated' (a human reviews/approves
// each action before it executes) or 'autonomous' (no per-action human approval).
// See Agent Attribution above. There is no default — you must choose.
declare const DECISION_ORIGIN: 'human_mediated' | 'autonomous';
const AGENT_INFO = JSON.stringify({
  integration_name: 'swap-integration',
  decision_origin: DECISION_ORIGIN,
  version: '1.5.0',
});
const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
const publicClient = createPublicClient({ chain: mainnet, transport: http() });
const walletClient = createWalletClient({ account, chain: mainnet, transport: http() });
// Helper to prepare /swap request body — routing-aware permitData handling
function prepareSwapRequest(quoteResponse: Record<string, unknown>, signature?: string): object {
  const { permitData, permitTransaction, ...cleanQuote } = quoteResponse;
  const request: Record<string, unknown> = { ...cleanQuote };
  // UniswapX (DUTCH_V2, DUTCH_V3, PRIORITY): permitData is for LOCAL signing only.
  // The /swap body must NOT include permitData — the order is already encoded
  // in quote.encodedOrder. Only the signature is needed.
  const isUniswapX =
    quoteResponse.routing === 'DUTCH_V2' ||
    quoteResponse.routing === 'DUTCH_V3' ||
    quoteResponse.routing === 'PRIORITY';
  if (isUniswapX) {
    if (signature) request.signature = signature;
  } else {
    // CLASSIC: both signature and permitData required together, or both omitted
    if (signature && permitData && typeof permitData === 'object') {
      request.signature = signature;
      request.permitData = permitData;
    }
  }
  return request;
}
// Validate swap response before broadcasting
function validateSwap(swap: { data?: string; to?: string; from?: string }): void {
  if (!swap?.data || swap.data === '' || swap.data === '0x') {
    throw new Error('swap.data is empty - quote may have expired');
  }
  if (!isHex(swap.data)) {
    throw new Error('swap.data is not valid hex');
  }
  if (!swap.to || !isAddress(swap.to) || !swap.from || !isAddress(swap.from)) {
    throw new Error('Invalid address in swap response');
  }
}
async function executeSwap(tokenIn: Address, tokenOut: Address, amount: string, chainId: number) {
  const ETH_ADDRESS = '0x0000000000000000000000000000000000000000';
  // 1. Check approval (for ERC20 tokens, not native ETH)
  if (tokenIn !== ETH_ADDRESS) {
    const approvalRes = await fetch(`${API_URL}/check_approval`, {
      method: 'POST',
      headers: {
        'x-api-key': API_KEY,
        'Content-Type': 'application/json',
        'x-universal-router-version': '2.0',
        'x-agent-info': AGENT_INFO,
      },
      body: JSON.stringify({
        walletAddress: account.address,
        token: tokenIn,
        amount,
        chainId,
      }),
    });
    const approvalData = await approvalRes.json();
    if (approvalData.approval) {
      const hash = await walletClient.sendTransaction({
        to: approvalData.approval.to,
        data: approvalData.approval.data,
        value: BigInt(approvalData.approval.value || '0'),
      });
      await publicClient.waitForTransactionReceipt({ hash });
    }
  }
  // 2. Get quote
  const quoteRes = await fetch(`${API_URL}/quote`, {
    method: 'POST',
    headers: {
      'x-api-key': API_KEY,
      'Content-Type': 'application/json',
      'x-universal-router-version': '2.0',
      'x-agent-info': AGENT_INFO,
    },
    body: JSON.stringify({
      swapper: account.address,
      tokenIn,
      tokenOut,
      tokenInChainId: String(chainId),
      tokenOutChainId: String(chainId),
      amount,
      type: 'EXACT_INPUT',
      slippageTolerance: 0.5,
    }),
  });
  const quoteResponse = await quoteRes.json(); // Store FULL response
  if (!quoteRes.ok) {
    throw new Error(quoteResponse.detail || 'Quote failed');
  }
  // 3. Execute swap - CRITICAL: spread quote response, strip null fields
  const swapRequest = prepareSwapRequest(quoteResponse);
  const swapRes = await fetch(`${API_URL}/swap`, {
    method: 'POST',
    headers: {
      'x-api-key': API_KEY,
      'Content-Type': 'application/json',
      'x-universal-router-version': '2.0',
      'x-agent-info': AGENT_INFO,
    },
    body: JSON.stringify(swapRequest),
  });
  const swapData = await swapRes.json();
  if (!swapRes.ok) {
    throw new Error(swapData.detail || 'Swap request failed');
  }
  // 4. Validate before broadcasting
  validateSwap(swapData.swap);
  const hash = await walletClient.sendTransaction({
    to: swapData.swap.to,
    data: swapData.swap.data,
    value: BigInt(swapData.swap.value || '0'),
  });
  return publicClient.waitForTransactionReceipt({ hash });
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
 
interface IUniversalRouter {
    function execute(
        bytes calldata commands,
        bytes[] calldata inputs,
        uint256 deadline
    ) external payable;
}
 
interface IERC20 {
    function approve(address spender, uint256 amount) external returns (bool);
}
 
contract SwapIntegration {
    IUniversalRouter public immutable router;
    address public constant PERMIT2 = 0x000000000022D473030F116dDEE9F6B43aC78BA3;
 
    constructor(address _router) {
        router = IUniversalRouter(_router);
    }
 
    function swap(
        bytes calldata commands,
        bytes[] calldata inputs,
        uint256 deadline
    ) external payable {
        router.execute{value: msg.value}(commands, inputs, deadline);
    }
 
    // Approve token for Permit2 (one-time setup)
    function approveToken(address token) external {
        IERC20(token).approve(PERMIT2, type(uint256).max);
    }
}

// After getting swap calldata from Trading API:
const { to, data, value } = swapResponse.swap;
// Wrap in delegation execution
const execution = {
  target: to, // Universal Router
  callData: data,
  value: BigInt(value),
};
// Submit via bundler — use sendUserOperation directly
const userOpHash = await bundlerClient.sendUserOperation({
  account: delegateSmartAccount,
  calls: [
    {
      to: delegationManagerAddress,
      data: encodeFunctionData({
        abi: delegationManagerAbi,
        functionName: 'redeemDelegations',
        args: [[[signedDelegation]], [0], [[execution]]],
      }),
      value: execution.value,
    },
  ],
});

import { parseAbi, type Address } from 'viem';
const WETH_ABI = parseAbi([
  'function balanceOf(address) view returns (uint256)',
  'function withdraw(uint256)',
]);
const WETH_ADDRESSES: Record<number, Address> = {
  1: '0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2',
  10: '0x4200000000000000000000000000000000000006',
  8453: '0x4200000000000000000000000000000000000006',
  42161: '0x82aF49447D8a07e3bd95BD0d56f35241523fBab1',
};
// After swap completes on an L2:
const wethAddress = WETH_ADDRESSES[chainId];
if (wethAddress) {
  const wethBalance = await publicClient.readContract({
    address: wethAddress,
    abi: WETH_ABI,
    functionName: 'balanceOf',
    args: [accountAddress],
  });
  if (wethBalance > 0n) {
    const hash = await walletClient.writeContract({
      address: wethAddress,
      abi: WETH_ABI,
      functionName: 'withdraw',
      args: [wethBalance],
    });
    await publicClient.waitForTransactionReceipt({ hash });
  }
}

// Exponential backoff for 429 responses
async function fetchWithRetry(url: string, init: RequestInit, maxRetries = 5): Promise<Response> {
  for (let attempt = 0; attempt <= maxRetries; attempt++) {
    const response = await fetch(url, init);
    if (response.status !== 429 && response.status < 500) return response;
    if (attempt === maxRetries) throw new Error(`Failed after ${maxRetries} retries`);
    const delay = Math.min(200 * Math.pow(2, attempt) + Math.random() * 100, 10000);
    await new Promise((resolve) => setTimeout(resolve, delay));
  }
  throw new Error('Unreachable');
}