Swapping Tokens

Use the fdx call swapTokens command to swap between tokens via decentralized exchanges on any supported chain. Unlike centralized exchange swaps, these execute directly on-chain through DEX protocols.

Confirm wallet is authenticated

fdx status

If the wallet is not authenticated, refer to the authenticate skill.

Check Balance Before Swapping

Verify the wallet holds enough of the source token:

fdx call getWalletOverview --chainKey <chain>

Executing a Swap

fdx call swapTokens \
  --chainKey <chain> \
  --tokenIn <token> \
  --tokenOut <token> \
  --amount <amount>

Parameters

Parameter	Required	Description
--chainKey	Yes	Blockchain to swap on (e.g. ethereum, polygon, base, solana)
--tokenIn	Yes	Source token — symbol (e.g. USDC, ETH) or contract address
--tokenOut	Yes	Destination token — symbol or contract address
--amount	Yes	Amount of tokenIn to swap (human-readable)
--mode	No	Swap mode (e.g. exact input, exact output)
--objective	No	Optimization objective (e.g. best price, lowest gas)
--maxSlippageBps	No	Maximum slippage tolerance in basis points (100 = 1%)
--deadlineSeconds	No	Transaction deadline in seconds

Examples

Basic swaps

# Swap 100 USDC for ETH on Ethereum
fdx call swapTokens \
  --chainKey ethereum \
  --tokenIn USDC \
  --tokenOut ETH \
  --amount 100

# Swap 0.05 ETH for USDC on Base
fdx call swapTokens \
  --chainKey base \
  --tokenIn ETH \
  --tokenOut USDC \
  --amount 0.05

# Swap SOL for USDC on Solana
fdx call swapTokens \
  --chainKey solana \
  --tokenIn SOL \
  --tokenOut USDC \
  --amount 2

Swap with slippage control

# Swap with 0.5% max slippage
fdx call swapTokens \
  --chainKey ethereum \
  --tokenIn USDC \
  --tokenOut ETH \
  --amount 500 \
  --maxSlippageBps 50

Swap using contract addresses

# Swap using explicit token contract addresses
fdx call swapTokens \
  --chainKey ethereum \
  --tokenIn 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 \
  --tokenOut 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 \
  --amount 100

Flow

1. Check authentication with fdx status
2. Check balance with fdx call getWalletOverview --chainKey <chain>
3. Confirm the swap details with the human (amount, tokens, chain, slippage)
4. Execute with fdx call swapTokens
5. Optionally check updated balance with fdx call getWalletOverview

Important: DEX swaps are subject to slippage — the final output amount may differ slightly from the quoted amount. For large swaps, consider setting --maxSlippageBps explicitly.

Prerequisites

• Must be authenticated (fdx status to check, see authenticate skill)
• Wallet must hold sufficient balance of the source token on the target chain
• If the wallet has insufficient funds, suggest using the fund-wallet skill

Error Handling

• "Not authenticated" — Run fdx setup first, or see authenticate skill
• "Insufficient balance" — Check balance with getWalletOverview; see fund-wallet skill
• "Cannot swap a token to itself" — tokenIn and tokenOut must be different
• "No liquidity" — Try a smaller amount or a different token pair
• "Swap failed" — May be a slippage issue; try with a higher --maxSlippageBps