How to add fee in ERC20 token?

Smart Contracts
1

Hello, I just try simple code and adding fee each time I transfer, however I can add liquidity on uniswap but I can't buy it when fee > 0. Anyone can help me why this code is failed ?

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1 Like
2

Yeah I know the reason, I have to put slippage greater than fee to do the transaction

3

Most likely, the uniswap pool contract verifies that the full amount has been transferred into itself.

Regardless, I'd change this:

if (fee > 0) {
    uint256 _fee = _transferAmount * fee / 10000;
   ...
}

To this:

uint256 _fee = _transferAmount * fee / 10000;
if (_fee > 0) {
   ...
}
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4

Take in mind that Uniswap v3 doesn't support token with fees

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5

Well, that's pretty much what I've speculated above.

1 Like
6

you may try the swap function which support fee on transfer.
like swapExactTokensForTokensSupportingFeeOnTransferTokens(), swapExactETHForTokensSupportingFeeOnTransferTokens(), swapExactTokensForETHSupportingFeeOnTransferTokens.