Approval-and-Swap Combo Executor

WHAT IT DOES

Approval-and-Swap Combo Executor lets you approve a token and execute a DEX swap in one atomic batched transaction. Instead of submitting two separate transactions—first an approve() to grant the router permission, then the swap itself—the tool bundles both calls into a single multicall transaction. This saves gas, reduces wallet signing steps, and eliminates the race condition where a swap fails because the approval wasn't submitted or confirmed in time. You get a quote first, then execute the combo with slippage protection.

HOW TO USE

Connect your EVM wallet and select the network. Enter the DEX router address (e.g., Uniswap V2 Router), the input token address, the output token address, and the amount in wei. Set your slippage tolerance percentage. Click "Get quote" to see the expected output and exchange rate. Review the details, then click "Execute combo (approve + swap)". The tool checks your balance and current allowance, then builds a batch containing an approve() call (if needed) and the swap call. The entire batch is submitted via multicall and confirmed in one transaction.

TECHNICAL MECHANISM

The tool uses Multicall3 to aggregate multiple contract calls into a single transaction. It first checks the token balance and current allowance for the router. If the allowance is less than the amount to swap, it encodes an approve(spender, amount) call for the input token. It then encodes a swap call—typically swapExactTokensForTokens()—using the router's interface, with the amountOutMin calculated from the quote and slippage tolerance. Both calls are packaged into an aggregate3() call and submitted. The tool uses receipt.effectiveGasPrice for accurate gas reporting and provides progress feedback during execution. The swap path is a simple two-token path (tokenIn → tokenOut).

WHAT IT CANNOT SEE

This tool cannot handle swaps that require multiple approval steps or complex routing beyond a standard ERC-20 approval plus a simple swap. It does not detect or handle tokens with non-standard approve() behavior (e.g., tokens that return false instead of reverting, or that use permit/transferFrom patterns). It relies on the DEX router contract supporting the expected interface and on the multicall contract being deployed at the standard address. Slippage protection is applied but cannot guarantee protection against extreme front-running or network congestion. The tool does not support native token (ETH/BNB) swaps—only ERC-20 to ERC-20 swaps.

PLEASE NOTE

The combo transaction requires sufficient native tokens (ETH, BNB, MATIC, etc.) to cover gas fees. The multicall contract address used is the standard Multicall3 address—ensure it is deployed on your chosen network. Always verify the quote and slippage before executing. This tool is for EVM chains only and does not support non-EVM networks.