How to Swap Tokens

This guide will walk you through the process of getting optimal swap quotes and executing secure transactions using the DuckyDux API.

DuckyDux automatically finds the best route across multiple DEXs including Uniswap, Curve and more to get you the best possible price.

Get a Swap Quote

DuckyDux provides intelligent multi-path routing to find the optimal swap route across multiple liquidity sources.

cURL


curl "https://api.duckydux.com/v1/swap/quote" \
  -G \
  -d "sources=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE" \
  -d "sinks=0x6B175474E89094C44Da98b954EedeAC495271d0F" \
  -d "supplies=1000000000000000000" \
  -d "demands=-1" \
  -d "slippage=0.5" \
  -d "sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045" \
  -d "check_approvals=true"

JavaScript


const params = new URLSearchParams({
  sources: '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE', // ETH
  sinks: '0x6B175474E89094C44Da98b954EedeAC495271d0F',   // DAI
  supplies: '1000000000000000000', // 1 ETH in wei
  demands: '-1', // Unlimited demand
  slippage: '0.5',
  sender: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
  check_approvals: 'true'
});
 
const response = await fetch(`https://api.duckydux.com/v1/swap/quote?${params}`);
const quote = await response.json();

Python


import requests
 
params = {
    'sources': '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE',  # ETH
    'sinks': '0x6B175474E89094C44Da98b954EedeAC495271d0F',    # DAI
    'supplies': '1000000000000000000',  # 1 ETH in wei
    'demands': '-1',  # Unlimited demand
    'slippage': '0.5',
    'sender': '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    'check_approvals': True
}
 
response = requests.get('https://api.duckydux.com/v1/swap/quote', params=params)
quote = response.json()

Parameter	Description	Example
`sources`	Token addresses you’re selling	`0xEee...` (ETH)
`sinks`	Token addresses you’re buying	`0x6B1...` (DAI)
`supplies`	Amounts to sell in the token’s smallest unit (e.g., wei for ETH).	`1000000000000000000`
`demands`	Desired amounts to buy (`-1` for unlimited)	`-1`
`slippage`	Slippage tolerance (%)	`0.5`
`sender`	Transaction sender address	`0xd8d...`
`check_approvals`	Include approval transactions	`true`

Understanding the Quote Response

The API returns detailed routing information and transaction data:


{
  "routes": [
    {
      "amount": "1000000000000000000",
      "route": [...], // Multi-hop routing details
      "price": "2847.125",
      "minOutput": "2832.556875000000000000",
      "usdInput": 2847.12,
      "usdOutput": 2832.56,
      "cost": 14.56,
      "gas": 180000
    }
  ],
  "approvals": [...], // If approval needed
  "txs": [...], // Transaction data
  "gasPrice": "20000000000"
}

Always verify the minOutput amount and gas costs before proceeding with the transaction.

Handle Token Approvals

When swapping ERC20 tokens, you may need to approve the DuckyDux router to spend your tokens.

Check Response

If check_approvals=true was set in your quote request, approval transactions will be automatically included in the response:


{
  "approvals": [
    {
      "token": {
        "addr": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
        "symbol": "USDC",
        "decimals": 6
      },
      "amount": "1000000",
      "tx": {
        "to": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
        "data": "0x095ea7b3...",
        "gas": 46000
      }
    }
  ]
}

Execute the Swap

Security Best Practice: For maximum security and MEV protection, bundle approval and swap transactions together. Avoid sending approval transactions separately as this exposes your intent to MEV bots.

Common Swap Scenarios

💎 ETH to ERC20 🔄 ERC20 to ERC20 🔀 Multi-token Swap

ETH to ERC20

The simplest swap type - no approvals needed:


// ETH → USDC swap
const quote = await fetch(
  'https://api.duckydux.com/v1/swap/quote?' +
    new URLSearchParams({
      sources: '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE',
      sinks: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48',
      supplies: '1000000000000000000', // 1 ETH
      demands: '-1',
      slippage: '0.5',
      sender: userAddress,
    })
)

ERC20 to ERC20

Requires token approval - use bundling for security:

DuckyDux automatically handles complex routing through multiple DEXs to find the best price for ERC20-to-ERC20 swaps.


// USDC → DAI swap with approval check
const quote = await fetch(
  'https://api.duckydux.com/v1/swap/quote?' +
    new URLSearchParams({
      sources: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48', // USDC
      sinks: '0x6B175474E89094C44Da98b954EedeAC495271d0F', // DAI
      supplies: '1000000', // 1 USDC (6 decimals)
      demands: '-1',
      slippage: '0.5',
      sender: userAddress,
      check_approvals: 'true',
    })
)
 
// If approval needed, bundle with swap for security
if (quote.approvals.length > 0) {
  // Send as bundle - see "Using Transaction Bundles" guide
}

Multi-token Swap

Advanced scenario with multiple sources or sinks:


// Swap multiple tokens to ETH
const sources = [
  '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48', // USDC
  '0x6B175474E89094C44Da98b954EedeAC495271d0F', // DAI
]
const sinks = ['0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE'] // ETH
const supplies = ['1000000', '1000000000000000000'] // 1 USDC, 1 DAI
const demands = ['-1']
 
const params = new URLSearchParams()
sources.forEach(source => params.append('sources', source))
sinks.forEach(sink => params.append('sinks', sink))
supplies.forEach(supply => params.append('supplies', supply))
demands.forEach(demand => params.append('demands', demand))
params.append('slippage', '1.0')
params.append('sender', userAddress)
params.append('check_approvals', 'true')
 
const quote = await fetch(`https://api.duckydux.com/v1/swap/quote?${params}`)

Next Steps

🔗 Bundle Transactions ⛽ Gas Sponsorship 🛠️ Error Handling