Send BTC

[Jayke770]

I'm sending BTC to another address how can I change/override the change address?

Tx Link: https://blockchair.com/bitcoin/testnet/transaction/964543edcaaeeecd8d77a41046369c2493b525779f1417007058b0b0f95d0228

[mccwdev]

You can spend a single utxo and specify all output addresses like this:

wallet = wallet_delete_if_exists('example_btctestnet', force=True)
w = Wallet.create('example_btctestnet', network='bitcoinlib_test')
w.utxos_update()
t = w.send([('blt1qwx3vf0jlwpxvc5cl9g6gj4sltpluqem9jt0cde', 50000000),
            ('blt1qlkwskkwudqgee9az2cjqgncns5phykwx6eav3t', 49999000)], fee=1000, max_utxos=1)
t.info()

You can also use the input_arr or input_key_id argument to use specific utxo's

[mikeywaites]

Hey @mccwdev . hoping you can build on your answer to help me understand how this works.

I have this simple code example

def send_tx():
    # Create wallet
    recipient_address = "bc1pqmeagf32qlcyd8ehhuwzfyj5r3mmfqe75uuxw53cz3g7pxt8cafqphwjch"
    amount = 8000
    wallet = wallet_create_or_open(
        "dev", seed_phrase, network="bitcoin", witness_type="p2sh-segwit"
    )

    wallet.scan(account_id=0)

    t = wallet.send_to(
        recipient_address,
        amount,
        offline=True,
        account_id=0,
        number_of_change_outputs=1,
    )

    print(t.info())

This creates a transaction like i'd expect.

Transaction 9d835c6a3456c0d12fea5b6efd187ddfdf35c701aed9b1012eccdbeaf942e89b
Date: None
Network: bitcoin
Version: 1
Witness type: segwit
Status: new
Verified: True
Inputs
- 37R8sDNcVYjyAr4mcPrDQoSiuXtwyUF3y9 0.02123440 BTC 300fdbf0753e4acc001f56e0ac17c2ed07b96378a4a06c3b3e6468726c2b501c 0
  p2sh-segwit sig_pubkey; sigs: 1 (1-of-1) valid
Outputs
- bc1pqmeagf32qlcyd8ehhuwzfyj5r3mmfqe75uuxw53cz3g7pxt8cafqphwjch 0.00008000 BTC p2tr U
- 36mZ2dqYZJNe5DH1m8Ze3kXkn4jVq1ScKq 0.02112400 BTC p2sh U
Size: 258
Vsize: 177
Fee: 3040
Confirmations: None
Block: None
Pushed to network: False
Wallet: dev

What i cannot for the life of me figure out is, how do i have the output to send the unspent UTXOs back to my wallet go back to the same address that the Inputs came from.

To be clear, this address is the address with the inputs, i want everything i dont spent to then go back to this address.

37R8sDNcVYjyAr4mcPrDQoSiuXtwyUF3y9

so that the transaction info looks like this

Transaction 9d835c6a3456c0d12fea5b6efd187ddfdf35c701aed9b1012eccdbeaf942e89b
Date: None
Network: bitcoin
Version: 1
Witness type: segwit
Status: new
Verified: True
Inputs
- 37R8sDNcVYjyAr4mcPrDQoSiuXtwyUF3y9 0.02123440 BTC 300fdbf0753e4acc001f56e0ac17c2ed07b96378a4a06c3b3e6468726c2b501c 0
  p2sh-segwit sig_pubkey; sigs: 1 (1-of-1) valid
Outputs
- bc1pqmeagf32qlcyd8ehhuwzfyj5r3mmfqe75uuxw53cz3g7pxt8cafqphwjch 0.00008000 BTC p2tr U
- 37R8sDNcVYjyAr4mcPrDQoSiuXtwyUF3y9 0.02112400 BTC p2sh U
Size: 258
Vsize: 177
Fee: 3040
Confirmations: None
Block: None
Pushed to network: False
Wallet: dev

appreciate any help

[mccwdev]

You have to send function and not the send_to, supply a list of addresses and the fee. The total value output of the addresses plus the fee has to be the same as the input value, then no extra change address will be created.

In the example above there are two outputs and a fee of 1000, which adds up to 100000000, which is equal to one test utxo.

[mikeywaites]

@mccwdev thanks for getting back to me.

is there an example of the above you could point me to or possibly provide some code example

[mccwdev]

Not sure what you are want to achieve, but this kind of address reuse is not good for privacy and safety.

However you could do something like

w = wallet_create_or_open('wlt373', network='testnet')
w.scan(scan_gap_limit=1)
w.info()

output_arr = [
    ('tb1qyqjgxn8aycwgxjjgnzpen6u5z4tsmnyjhhf300', 400),
    ('tb1qplyhtmgdk0hjuevux22xvudvljkvw5cpgr4tkv', 400),
]

t = w.send(output_arr, fee=200, min_confirms=0, offline=False)
t.info()

Tx info: https://blocksmurfer.io/tbtc/transaction/1b533e9942974953974f3627c5151e767b14245765c9b12c56d1bbdaec09f6ed