When you send from your Bitaroo Wallet, the app normally decides which UTXOs to spend. If you would rather decide yourself, you can choose them. If UTXOs are new to you, start with What is a UTXO?
To choose UTXOs for a send
- Open your Wallet and select UTXOs.
- Select Choose UTXOs to send.
- Tap each UTXO you want to use. The number chosen and their total are shown at the bottom of the screen. Frozen UTXOs are dimmed and cannot be chosen.
- Select Send from these UTXOs.
- The Send screen opens with your choice shown at the top, for example "From 2 chosen UTXOs". Enter the address and the amount, review, and confirm as usual.
To send from a single UTXO, tap it in the list and select Send this UTXO. To pick again, select Change at the top of the Send screen.
How your choice is used
- Only the UTXOs you chose can be spent. The amount available on the Send screen is the total of your choice.
- A set amount uses as many of them as it needs. If one of your chosen UTXOs covers the amount and the network fee, your Wallet may spend only that one. The review screen tells you how many it will spend, for example "1 of 2 chosen UTXOs".
- Max spends all of them. Select Max to send everything in your chosen UTXOs, less the network fee.
- Anything left over comes back to you. It returns to your Wallet as a new UTXO, shown in the list as Change.
- Your choice applies to one send. Once that send completes, your Wallet goes back to deciding for you.
When choosing is useful
- Keeping UTXOs apart. UTXOs spent in the same transaction are linked on the blockchain. Choosing lets you decide which ones are spent together.
- Spending a particular UTXO. For example, one you have marked with a note.
- Combining small UTXOs. Each UTXO a send spends adds to its network fee. When fees are low you can combine several small UTXOs into one: choose them, enter an address from your own Wallet's Receive screen, and select Max. You pay a network fee for this, and combining UTXOs also links them.
If a send does not go through
- "One of your chosen UTXOs is no longer available. Choose again." A UTXO you picked has since been spent or frozen. Your choice is cleared, so the send cannot quietly draw on other UTXOs. Go back to the UTXOs screen and choose again.
- "That is more than your chosen UTXOs hold." Lower the amount, select Max, or select Change and add another UTXO.
- "Not enough for the fee". The amount fits within your choice, but not together with the network fee. The app offers to send all of your chosen UTXOs less the fee instead.
- "The UTXOs this send would spend changed since you reviewed." Your Wallet checks again just before sending. If it would no longer spend the UTXOs you reviewed, it shows the updated details for you to confirm.