0x-swap

0x Protocol DEX aggregator. Swap tokens at the best rates across 9+ liquidity sources on Ethereum, Polygon, BSC, and more.

Install with Tessl CLI

npx tessl i github:Demerzels-lab/elsamultiskillagent --skill 0x-swap

What are skills?

Overall
score

60%

Review — 48%

Does it follow best practices?

If you maintain this skill, you can automatically optimize it using the tessl CLI to improve its score:

npx tessl skill review --optimize ./path/to/skill

Learn more

Validation — 9 / 11 Passed

Validation for skill structure

SKILL.md

Review

Evals

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

ALWAYS display swap details before execution
WARN if price impact > 1%
CHECK token allowance before swap
VERIFY output amount matches quote
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