tools-only ETH-to-Token Swap Test Case
Build a swap integration that handles native ETH as the input token, including the ETH wrapping step.
Context
- TypeScript/Node.js backend script
- Need to swap native ETH to USDC on Ethereum mainnet
- Using the Uniswap Trading API
- Have a private key for signing
Requirements
- Detect that the input token is native ETH (address 0x0000000000000000000000000000000000000000 or similar sentinel)
- Skip the /check_approval step for native ETH (no approval needed for native tokens)
- Get a quote via /quote with the ETH sentinel address as tokenIn
- Handle the swap response value field correctly (must send ETH value with the transaction)
- Strip null permitData fields from the swap request before sending
- Validate swap.data is non-empty before broadcasting
- Set the transaction value to the ETH amount being swapped (not "0")
Constraints
- Must use the Uniswap Trading API (https://trade-api.gateway.uniswap.org/v1)
- Must correctly distinguish native ETH from ERC-20 token flows
- Must handle the value field in the swap response (ETH swaps require msg.value)
- Must not call /check_approval for native ETH inputs
- Should include error handling for API failures and transaction reverts
Edge Cases to Handle
- The swap response value field will be non-zero for ETH inputs
- The quote response may still contain permitData: null even for ETH swaps
- Gas estimation should account for the ETH value being sent
Expected Output
A working TypeScript implementation that demonstrates swapping native ETH to an ERC-20 token via the Trading API, correctly handling the ETH-specific flow (skipping approval, passing transaction value, stripping null fields).