At times, the bitcoin network experiences very high transaction delays for transactions made with low fee levels.
It's possible you're reading this because your transaction got stuck in the mempool.
The fee estimate given to you by the Casa app changes from block to block based on recent past network activity. While the app does try to give you the best fee estimate, there's never a guarantee that any transaction will confirm on the blockchain.
Generally speaking, transactions sent with a higher fee will confirm faster.
Most transfers that are sent from the Casa app with a low fee do eventually confirm. If you are not in a hurry to send your transaction, the best solution may be just to wait for it to confirm.
Even in times that your transaction takes an abnormally long time to confirm, your funds are safe. If it doesn't confirm and is dropped from the mempool, then the funds will be "returned" to your wallet as if the transaction never took place (though cached data may still show the transaction in your Casa app). At that time, you'll have the option to send it again with a higher fee.
Does Casa support RBF?
RBF (Replace By Fee) is a bitcoin feature that allows you to send a second transaction with a higher fee to replace the first. Casa does not currently support RBF.
How do I make my transaction go faster?
Once a transaction is broadcast and propagated throughout the network, there is very little you can do to "unsend" it or change it. If your transaction is urgent, there are a couple options available to you in your Casa app, detailed below.
CPFP
If the transaction is still in the mempool and the receiving wallet supports it, you can try something called CPFP (Child Pays For Parent https://bitcoinops.org/en/topics/cpfp/). To do this, the receiving wallet would have to send the unconfirmed UTXO.
Make sure to choose a fee rate high enough to ensure it will be mined.
You may find that the external wallet you sent to does not allow you to send unconfirmed UTXOs. If that is the case, you would not be able to do CPFP unless you had a way of sending the UTXO from a different wallet (e.g., loading your seed phrase into something like Electrum).
Recreate the transaction
If the fee is low enough, it may temporarily be dropped from the Casa mempool. In this case, you can recreate the transaction and send it again.
It's important that you recreate the transaction with the exact same UTXO(s), otherwise you may accidentally send a different UTXO without meaning to, and your original transaction will remain unchanged.
Here are the steps you can take:
- Since your transaction is still in the mempool, you can view it in the Blockstream explorer by tapping the transaction from within the Casa app and writing down the UTXO(s) that are being sent.
- Wait for the transaction to be purged from the mempool. This happens when the size of the mempool grows larger than what is reasonably expected to confirm in several weeks time.
You could use this site for mempool visualization: https://mempool.space/ - Recreate the transaction. Make sure you send the exact same UTXO(s). You can do this in the Casa app by tapping the grey "Send From" button at the top of the screen when you are making a transaction.
- Sign and broadcast! It's important that you wait to do this until the transaction has been dropped from most mempools (Blockstream is a good indicator of this). Otherwise it will be rejected as a double spend.