how swap from 1 token to usdt without direct pair? and fees on swap from token to eth

[facilficom]

question 1:
I am trying the possibility of performing a swap from [Token] to USDT. However, I have noticed that there isn't a direct trading pair available for this token and USDT. The swap with 3 paths is not working for me.

question 2:
Is it possible to swap the fees to WETH and then unwrap WETH to ETH in the same transaction? If so, how can I achieve this using the Universal Router? i can take the fee from amountout like explain in a discussion before this but i cannot swap to weth and then eth in the same transaction

[Elnaril]

Hi @facilficom !
For both questions, could you share the code you tried so far?

[facilficom]

here, is for other conditions:
path = [token_sold, token_bought]
recipient_rate = int((1 - COMMISSION_RATE) * 10000)
if eth_value:
chain_builder = chain_builder.v2_swap_exact_in(FunctionRecipient.ROUTER, amount_sold, 0, path, payer_is_sender=True)
chain_builder = chain_builder.unwrap_weth(FunctionRecipient.ROUTER, 0)
chain_builder = chain_builder.pay_portion(FunctionRecipient.SENDER, '0x0000000000000000000000000000000000000000', recipient_rate)
chain_builder = chain_builder.sweep(FunctionRecipient.CUSTOM, '0x0000000000000000000000000000000000000000', 0, OWNER_WALLET_ADDRESS)
else:
chain_builder = chain_builder.v2_swap_exact_in(FunctionRecipient.ROUTER, amount_sold, 0, path, payer_is_sender=True)
chain_builder = chain_builder.pay_portion(FunctionRecipient.SENDER, token_bought, recipient_rate)
if token_bought.lower() == weth_address.lower():
chain_builder = chain_builder.unwrap_weth(FunctionRecipient.CUSTOM, 0, OWNER_WALLET_ADDRESS)
else:
chain_builder = chain_builder.sweep(FunctionRecipient.CUSTOM, token_bought, 0, OWNER_WALLET_ADDRESS)

encoded_input = chain_builder.build(codec.get_default_deadline())

trx_params = {
    "from": account_checksum,
    "to": uniswap_address,
    "maxPriorityFeePerGas": maxpriorityfeepergas,
    "maxFeePerGas": maxfeepergas,
    "type": '0x2',
    "chainId": chain_id,
    "value": 0,
    "nonce": nonce,
    "data": encoded_input,
}
trx_params_gas_estimate = web3.eth.estimate_gas(trx_params)
trx_params.update({'gas': int(trx_params_gas_estimate * 1.2)})
signed_transaction = web3.eth.account.sign_transaction(trx_params, private_key)
trx_hash = web3.eth.send_raw_transaction(signed_transaction.raw_transaction)
print(f"Transaction Hash: {trx_hash.hex()}")
receipt = web3.eth.wait_for_transaction_receipt(trx_hash)
print(f"Transaction receipt: {receipt}")

after this:
else:
chain_builder = chain_builder.sweep(FunctionRecipient.CUSTOM, token_bought, 0, OWNER_WALLET_ADDRESS)
will be useful to swap the remain for eth becuase if its not possible, the owner wallet will have thousands of tokens.

in the while, if i make a path of 3 tokens (usdt, wbnb, token or viceversa) the transaction doesnt work

[Elnaril]

Ok, thanks!

So, if I understand correctly what you try to achieve, you'd like to swap the remaining tokens to WETH and unwrap to ETH instead of sweeping them in the following code block, right ?

else:
    chain_builder = chain_builder.sweep(FunctionRecipient.CUSTOM, token_bought, 0, OWNER_WALLET_ADDRESS)

In this case, if you have the right path, you can use the method v2_swap_exact_in_from_balance() to encode the swap to WETH using the full amount in the router's balance, then unwrap_weth().

The tricky part would be to have the right path. For that, you may want to give a try to the: uniswap-smart-path

---

For your issue with a 3-token path, could you please share a minimal example and a link to the failed transaction?

[facilficom]

yes, im trying but if i add swap in from balance the transaction give me an error, i dont think its possible to make 2 swap in the same data. for the 3 token path example, it seems on a universal router they passed the first amountout swap to the address pair and then make the other swap, i think this is the problem. https://bscscan.com/tx/0xff8b9f7daab571a44b7ba952c6b7fb471237f58975d0b16ac06a283f244e9e48#eventlog

[Elnaril]

for the 3 token path example, it seems on a universal router they passed the first amountout swap to the address pair and then make the other swap, i think this is the problem. https://bscscan.com/tx/0xff8b9f7daab571a44b7ba952c6b7fb471237f58975d0b16ac06a283f244e9e48#eventlog

This is the decoded input data used in the transaction you linked:

(<Function execute(bytes,bytes[],uint256)>,
 {'commands': b'\x08',
  'inputs': [(<Function V2_SWAP_EXACT_IN(address,uint256,uint256,address[],bool)>,
              {'recipient': '0xEd4FF665F61B36A63dFA260F6C8CcFB389d79C19',
               'amountIn': 162262162497017081,
               'amountOutMin': 386689736694041613984,
               'path': ['0x55d398326f99059fF775485246999027B3197955',
                        '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c',
                        '0xF3c7CECF8cBC3066F9a87b310cEBE198d00479aC'],
               'payerIsSender': True},
              {'revert_on_fail': True})],
  'deadline': 1721930957})

As you can see, there is a 3-token path. There is 2 swap events in the transaction logs because there is one per pool.

i dont think its possible to make 2 swap in the same data

If you look into the integration tests, you'll find some of them doing 2 swaps in the same transaction.