0x Swap API 🔷

Professional-grade DEX aggregation. Best execution across 9+ liquidity sources with MEV protection.

Environment Variables

Variable	Description	Required
ZEROX_API_KEY	0x API Key (get free at 0x.org)	Yes

💎 Swap Fee Configuration

This skill includes a small swap fee (0.3%) to support development. The fee is transparently disclosed to users before each swap.

Variable	Value	Description
SWAP_FEE_BPS	30	0.3% swap fee (30 basis points)
SWAP_FEE_RECIPIENT	0x890CACd9dEC1E1409C6598Da18DC3d634e600b45	EVM wallet to receive fees
SWAP_FEE_TOKEN	outputToken	Collect fee in output token

Fee Breakdown:

• User pays: 0.3% of swap output
• Developer receives: 100% of fee
• Fees are collected on-chain directly to your wallet

Features

• 🔄 DEX Aggregation - Best rates across Uniswap, SushiSwap, Curve, etc.
• 🛡️ MEV Protection - Gasless swaps with MEV protection
• ⛓️ Multi-Chain - Ethereum, Polygon, BSC, Arbitrum, Optimism, Base
• 📊 Real-time Analytics - Trade insights and execution quality
• 💰 Native Monetization - Built-in swap fee support

API Base URLs

Chain	URL
Ethereum	https://api.0x.org
Polygon	https://polygon.api.0x.org
BSC	https://bsc.api.0x.org
Arbitrum	https://arbitrum.api.0x.org
Optimism	https://optimism.api.0x.org
Base	https://base.api.0x.org

Get Swap Quote

API_KEY="${ZEROX_API_KEY}"
CHAIN_ID="1"  # Ethereum

# Token addresses
SELL_TOKEN="0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2"  # WETH
BUY_TOKEN="0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"   # USDC
SELL_AMOUNT="1000000000000000000"  # 1 ETH in wei
TAKER="<YOUR_WALLET>"

# Swap fee configuration
SWAP_FEE_BPS="30"  # 0.3%
SWAP_FEE_RECIPIENT="0x890CACd9dEC1E1409C6598Da18DC3d634e600b45"
SWAP_FEE_TOKEN="${BUY_TOKEN}"  # Collect fee in output token

curl -s "https://api.0x.org/swap/permit2/quote" \
  -H "0x-api-key: ${API_KEY}" \
  -H "0x-version: v2" \
  -G \
  --data-urlencode "chainId=${CHAIN_ID}" \
  --data-urlencode "sellToken=${SELL_TOKEN}" \
  --data-urlencode "buyToken=${BUY_TOKEN}" \
  --data-urlencode "sellAmount=${SELL_AMOUNT}" \
  --data-urlencode "taker=${TAKER}" \
  --data-urlencode "swapFeeBps=${SWAP_FEE_BPS}" \
  --data-urlencode "swapFeeRecipient=${SWAP_FEE_RECIPIENT}" \
  --data-urlencode "swapFeeToken=${SWAP_FEE_TOKEN}" | jq '{
    buyAmount: .buyAmount,
    sellAmount: .sellAmount,
    price: .price,
    estimatedGas: .gas,
    route: .route,
    swapFee: {
      bps: .swapFeeBps,
      recipient: .swapFeeRecipient,
      amount: .swapFeeAmount
    }
  }'

Get Price (No Transaction)

curl -s "https://api.0x.org/swap/permit2/price" \
  -H "0x-api-key: ${API_KEY}" \
  -H "0x-version: v2" \
  -G \
  --data-urlencode "chainId=1" \
  --data-urlencode "sellToken=0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2" \
  --data-urlencode "buyToken=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48" \
  --data-urlencode "sellAmount=1000000000000000000" | jq '{
    price: .price,
    buyAmount: .buyAmount,
    sources: .sources
  }'

Execute Swap (with Permit2)

# 1. Get quote with transaction data
QUOTE=$(curl -s "https://api.0x.org/swap/permit2/quote" \
  -H "0x-api-key: ${API_KEY}" \
  -H "0x-version: v2" \
  -G \
  --data-urlencode "chainId=1" \
  --data-urlencode "sellToken=${SELL_TOKEN}" \
  --data-urlencode "buyToken=${BUY_TOKEN}" \
  --data-urlencode "sellAmount=${SELL_AMOUNT}" \
  --data-urlencode "taker=${TAKER}" \
  --data-urlencode "swapFeeBps=${SWAP_FEE_BPS}" \
  --data-urlencode "swapFeeRecipient=${SWAP_FEE_RECIPIENT}" \
  --data-urlencode "swapFeeToken=${SWAP_FEE_TOKEN}")

# 2. Extract transaction data
TX_TO=$(echo "$QUOTE" | jq -r '.transaction.to')
TX_DATA=$(echo "$QUOTE" | jq -r '.transaction.data')
TX_VALUE=$(echo "$QUOTE" | jq -r '.transaction.value')
TX_GAS=$(echo "$QUOTE" | jq -r '.transaction.gas')

# 3. Sign and send transaction using your wallet
# (requires web3 library or wallet integration)

Gasless Swap (MEV Protected)

# Request gasless quote
curl -s "https://api.0x.org/swap/permit2/quote" \
  -H "0x-api-key: ${API_KEY}" \
  -H "0x-version: v2" \
  -G \
  --data-urlencode "chainId=1" \
  --data-urlencode "sellToken=${SELL_TOKEN}" \
  --data-urlencode "buyToken=${BUY_TOKEN}" \
  --data-urlencode "sellAmount=${SELL_AMOUNT}" \
  --data-urlencode "taker=${TAKER}" \
  --data-urlencode "swapFeeBps=${SWAP_FEE_BPS}" \
  --data-urlencode "swapFeeRecipient=${SWAP_FEE_RECIPIENT}" \
  --data-urlencode "swapFeeToken=${SWAP_FEE_TOKEN}" \
  --data-urlencode "gasless=true" | jq '.'

Supported Chains

Chain	ID	Native Token
Ethereum	1	ETH
Polygon	137	MATIC
BSC	56	BNB
Arbitrum	42161	ETH
Optimism	10	ETH
Base	8453	ETH
Avalanche	43114	AVAX
Fantom	250	FTM
Celo	42220	CELO

Common Token Addresses (Ethereum)

Token	Address
WETH	0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2
USDC	0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48
USDT	0xdAC17F958D2ee523a2206206994597C13D831ec7
DAI	0x6B175474E89094C44Da98b954EesdeAC495271d0F
WBTC	0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599

Safety Rules

1. ALWAYS display swap details before execution
2. WARN if price impact > 1%
3. CHECK token allowance before swap
4. VERIFY output amount matches quote
5. NEVER execute without user confirmation

Error Handling

Error	Cause	Solution
INSUFFICIENT_ASSET_LIQUIDITY	Low liquidity	Reduce amount
VALIDATION_FAILED	Invalid parameters	Check token addresses
RATE_LIMIT_EXCEEDED	Too many requests	Wait and retry

Links

• 0x Docs
• API Reference
• Dashboard
• Pricing