Uniswap swapping tokens issue

Question

I am trying to swap two tokens A and B for which I have created the pool on the Uniswap testnet Sepolia. But in Remix, when I try to execute the swap, it gives an error. Everything else is working fine, just this line is causing the issue.

This is the router address I have used for Sepolia, is it correct?

ISwapRouter public immutable uniswapRouter = ISwapRouter(0xE592427A0AEce92De3Edee1F18E0157C05861564);

function swapTokens(address _from, address _to, uint256 _amount) public{ require(_from!=_to,"Both the address can't be same"); require(userHolding[msg.sender][_from]>=_amount,"Sorry, you do not have the required amount of funds, please check the balance first"); // TransferHelper.safeApprove(_from, address(uniswapRouter), 0); TransferHelper.safeApprove(_from, address(uniswapRouter), 0); TransferHelper.safeApprove(_from, address(uniswapRouter), _amount); ISwapRouter.ExactInputSingleParams memory params = ISwapRouter.ExactInputSingleParams({ tokenIn: _from, tokenOut: _to, fee: poolFee, recipient: address(this), deadline: block.timestamp + 900, amountIn: _amount, amountOutMinimum: 0, sqrtPriceLimitX96: 0 }); // The call to `exactInputSingle` executes the swap. uint256 amountOut = uniswapRouter.exactInputSingle(params); // userHolding[msg.sender][_from]-=_amount; // userHolding[msg.sender][_to]+=amountOut; }

I tried everything, but the swap call is giving an error when I click on the swap button. It doesn't even let MetaMask open, it gives the error before.

Please edit to be specific about what error(s) you're getting and include their stack traces etc. See also How to Ask — agilgur5
– agilgur5, Commented Aug 12 at 22:59

Mariodoblep · Accepted Answer · 2025-08-12 21:14:03Z

1

The address you are using is incorrect for Sepolia. Use the actual SwapRouter address for Sepolia: 0x3bFA4769FB09eefC5a80d6E87c3B9C650f7Ae48E.

This should solve the main error that prevents MetaMask from opening.

answered Aug 12 at 21:14

Mariodoblep

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Community Aug 12 at 22:06

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